Hospital bed

ABSTRACT

A patient support including a frame and a mattress supported by the frame. The frame includes a deck support and a deck supporting the mattress.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/408,698, filed Sep. 6, 2002, titled HospitalBed; U.S. Provisional Patent Application Ser. No. 60/409,748, filed Sep.11, 2002, titled Bed Siderail; U.S. Provisional Patent Application Ser.No. 60/489,171, filed Jul. 22, 2003, titled Hospital Bed; and U.S.Provisional Patent Application Ser. No. 60/490,467, filed Jul. 28, 2003,titled Hospital Bed, the disclosures of which are expressly incorporatedby reference herein.

This application relates to U.S. patent application Ser. No. 09/750,741,filed Dec. 29, 2000, titled Hospital Bed, which claims the benefit ofU.S. Provisional Patent Application Ser. No. 60/173,428, filed Dec. 29,1999, titled Hospital Bed; U.S. patent application Ser. No. 09/751,031,filed Dec. 29, 2000, titled Foot Controls for a Bed, which claims thebenefit of U.S. Provisional Patent Application Ser. No. 60/173,428,filed Dec. 29, 1999, titled Hospital Bed; U.S. patent application Ser.No. 09/750,859, filed Dec. 29, 2000, titled Mattress Having aRetractable Foot Section, which claims the benefit of U.S. ProvisionalPatent Application Ser. No. 60/173,428, filed Dec. 29, 1999, titledHospital Bed; and U.S. patent application Ser. No. 10/225,780, filedAug. 22, 2002, titled Apparatus and Method for Closing Hospital BedGaps, which claims the benefit of U.S. Provisional Patent ApplicationSer. No. 60/397,342, filed Jul. 19, 2002, titled Apparatus and Methodfor Closing Hospital Bed Gaps and U.S. Provisional Patent ApplicationSer. No. 60/314,276, filed Aug. 22, 2001, titled Apparatus and Methodfor Closing Hospital Bed Gaps. This application further relates to PCTPatent Application No. PCT/US00/35656, filed Dec. 29, 2000, titledHospital Bed. The disclosures of all the above-mentioned patentapplications are expressly incorporated by reference herein.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a hospital bed. More particularly, thepresent invention relates to a hospital bed illustratively havingsiderails, an articulating deck, and a mattress.

Hospital bed and other patient supports are known. Typically, suchpatient supports are used to provide a support surface for patients orother individuals for treatment, recuperation, or rest. Many suchpatient supports include a frame, a deck supported by the frame, amattress, siderails configured to block egress of a patient from themattress, and a controller configured to control one or more features ofthe bed.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a perspective view of a patient support showing the patientsupport including a deck support, a deck having a plurality of sectionscoupled to and positioned above the deck support, a mattress supportedby the deck, a headboard coupled to the deck support, a first pair ofsiderails coupled to the deck, a second pair of siderails coupled to thedeck support, and foot pedal controls coupled to the deck support;

FIG. 2 is a perspective view of the patient support of FIG. 1 with thedeck, mattress, first pair of siderails and second pair of siderailsremoved and the headboard spaced apart from the deck support, the decksupport being in a raised position and comprising a base frame, anintermediate frame spaced apart from the base frame, a first pair oflifting arms configured to raise and lower a head end of theintermediate frame, and a second pair of lifting arms configured toraise and lower a foot end of the intermediate frame;

FIG. 3 is a side elevation view of the patient support of FIG. 1,showing the deck support in an upper position and the deck sections in alinear relationship or bed configuration;

FIG. 4 is a side elevation view of the patient support of FIG. 1,showing the deck support in the upper position of FIG. 3 and a headsection of the deck elevated by a head section actuator and a seatsection of the deck elevated by a seat section actuator;

FIG. 5 is a side elevation view of the patient support of FIG. 1,showing a first chair-like configuration of the patient support with thedeck support, the head section of the deck and the seat section of thedeck in generally the same positions as shown in FIG. 4 and aretractable leg section of the deck in the extended position and loweredby a leg section actuator;

FIG. 6 is a side elevation view generally similar to FIG. 5, showing theleg section of the deck in an extended position and the leg sectionbeing lowered by the leg actuator, the leg section not being fullylowered due to contact with an obstruction and the leg section and theobstruction prevented from damage by the leg section actuator travelingup an elongated slot provided in a coupling bracket between the legsection and the leg actuator;

FIG. 7 is a partial perspective view of the patient support of FIG. 2,showing the deck support in a lowered position wherein the intermediateframe nests within the base frame;

FIG. 8 is a top plan view of the patient support of FIG. 7, showing thenesting of the intermediate frame within the base frame;

FIG. 9 is a side elevation view of the patient support of FIG. 1,showing the deck support in a Trendelenburg position and the deck in alinear relationship;

FIG. 10 is a side elevation view of the patient support of FIG. 1,showing the patient support in a second chair-like position with thedeck support in a Reverse Trendelenburg position, the head sectionraised by the head actuator, the seat section elevated by the seatactuator, the leg section lowered by the leg actuator and the legsection optionally shown in the extended position;

FIG. 11 is a side elevation view generally similar to FIG. 10, showingthe leg section of the deck is in an extended position and the legsection being lowered by the leg actuator, the leg section not beingfully lowered due to contact with an obstruction, the floor, by a rollercoupled to the leg section and the leg section and the obstructionprevented from damage by the roller translating the leg section alongthe floor, the leg section rotating relative to the seat section and bythe leg section actuator traveling up the elongated slot provided in thecoupling bracket between the leg section and the leg actuator;

FIG. 12 is a side elevation view of the patient support of FIG. 1,showing the deck support in a Reverse Trendelenburg position, the headand seat sections of the deck in a generally linear relationship withthe leg section in an extended position and slightly angled relative tothe head and seat sections due to contact with an obstruction by theroller coupled to the leg section and the leg section and theobstruction prevented from damage by the roller translating the legsection relative to the obstruction, the leg section rotating relativeto the seat section and by the leg section actuator traveling up theelongated slot provided in the coupling bracket between the leg sectionand the leg actuator;

FIG. 13 is a perspective view of the deck and weigh frame of the patientsupport of FIG. 1 with the leg section removed and showing the headsection elevated;

FIG. 14 is a side view of one of the load cells which couple togetherthe intermediate frame and the weigh frame taken along lines 14-14 inFIG. 13;

FIG. 15 is a cross sectional view taken along lines 15-15 in FIG. 3,showing the coupling of the intermediate frame and the weigh frame witha load cell;

FIG. 16 is an upper perspective view of the deck and weigh frame of thepatient support of FIG. 1, showing the foot section in an extendedposition, the head section elevated relative to the seat section and apartition of the head section showing the manifold assembly on a firstside of the partition and first and second manifold receiving connectorson a second side of the partition;

FIG. 17 is a perspective view of the roller coupled to the end of thefoot section shown in FIG. 16;

FIG. 18 is a lower perspective view of the deck and the weigh frame ofthe patient support of FIG. 1, showing the foot section in a retractedposition, the seat section upwardly angled and the head section upwardlyangled;

FIG. 19 is a cross sectional view taken along lines 19-19 in FIG. 3,showing the gap between the deck and one of the foot end siderails;

FIG. 20 is generally similar to FIG. 18 showing the foot section of thepatient support in an extended position;

FIG. 21 is a perspective view of the leg section and a portion of theseat section of the deck and the mattress of FIG. 1, the leg sectionincluding a transverse recess positioned below retaining arms and theseat section including a pair of transverse recesses, the mattress beingshown spaced apart from the deck and configured to be coupled to theretaining arms of the leg section with a leg section anchor and to therecesses of the seat section with seat section anchors;

FIG. 22 is a side view of the deck and the weigh frame of the patientsupport of FIG. 1, showing the head, seat and leg sections of the deckin a linear relationship or bed configuration;

FIG. 23 is a detail view of a portion of the head section of the deck ofthe patient support of FIG. 1 showing a portion of a CPR systemcomprising a handle and handle bracket rotatably coupled to the deck andfurther coupled to a cable which is coupled to the actuator assembly ofFIGS. 27 and 28;

FIG. 24 is a bottom view of the deck and the weigh frame of FIG. 22;

FIG. 25 is a side view of the deck and the weigh frame of the patientsupport of FIG. 1, showing the head section elevated, the seat sectionelevated and the leg section elevated and generally horizontal;

FIG. 26 is detail view generally similar to FIG. 23 with the fastenerswhich couple the handle bracket to the deck not shown;

FIG. 27 is a perspective view of a actuator assembly of the CPR systemof the patient support showing a housing coupled to the cylinder rod ofthe actuator, a first embodiment of a slide bracket slidably coupled tothe housing and coupled to the cable which is further coupled to thehandle of FIG. 23 and a release pin of the actuator, and a switchlocated on the housing;

FIG. 28 is a perspective view of the actuator assembly of FIG. 27showing a second embodiment of the slide bracket, the slide brackethaving detents positively couple the ends of the cable;

FIG. 29 is a cross sectional view of the coupling of the secondembodiment of the slide bracket and the ends of the cable taken alonglines 29-29 of FIG. 28;

FIG. 30 is a perspective view of the caster braking system of thepatient support of FIG. 1 showing four caster devices, a first pair ofcaster devices being interconnected by a first transverse rod, a secondpair of caster devices being interconnected by a second transverse rodand the first and second pairs of caster devices being interconnected bya pair of longitudinal brake links;

FIG. 31 is a perspective view of a portion of the deck support of FIG. 2showing a first pair of caster devices, a battery housing, a batteryenable switch coupled to the battery housing and a communication linkcoupled to the battery housing;

FIG. 32 is a perspective view of the base frame of the deck support ofFIG. 2, showing a pedal and hexagonal rod of the caster braking systemspaced apart from the corresponding caster device and showing first andsecond brake links which interconnect a first pair of caster devices anda second pair of caster devices, the first and second brake links beingreceived within an interior of first and second longitudinal members ofthe base frame;

FIG. 33 is a perspective view of one of the caster devices of FIG. 32coupled to a first transverse rod and the first longitudinal brake link;

FIG. 34 is an end view of one of the caster devices shown in FIG. 32 andshowing the interconnection between the caster device, a hexagonal rod,a bracket configured to couple the hexagonal rod to the first brake linkand a transverse rod coupled to the hexagonal rod;

FIG. 35 is a block diagram illustrating the interconnection of variousmodules of an illustrative embodiment control system of a patientsupport of the present invention;

FIG. 35A is a block diagram detailing a portion of the control system ofFIG. 35 by illustrating the interconnection between various controlcomponents and the scale/ppm module, the dynamic surface module, theleft caregiver control module, and the right caregiver control module;

FIG. 35B is a block diagram detailing a portion of the control system ofFIG. 35 by illustrating the interconnection between various controlcomponents and the logic module;

FIG. 35C is a block diagram detailing a portion of the control system ofFIG. 35 by illustrating the interconnection between various controlcomponents and the sidecomm module;

FIG. 35D is a block diagram detailing a portion of the control system ofFIG. 35 by illustrating the interconnection between various controlcomponents and the power supply module;

FIG. 36 is a schematic diagram illustrating a plurality of objectdictionary entries of a Process Data Objects (PDO) protocol for use inconnection with a controller area network (CAN) of an illustrativeembodiment patient support of the present invention;

FIG. 37 is a waveform diagram of a message frame according to acommunications protocol for use in connection with a controller areanetwork (CAN) of an illustrative embodiment patient support of thepresent invention;

FIG. 38 is block diagram of an illustrative embodiment drive controlsystem in accordance with the present invention;

FIG. 39 is a side elevational view, in partial schematic, of anillustrative embodiment end of travel control system in accordance withthe present invention;

FIG. 40 is a flow diagram of an illustrative embodiment process formonitoring end of travel in accordance with the present invention;

FIG. 41 is a flow diagram of an illustrative embodiment duty cycleprotection process in accordance with the present invention;

FIG. 42 is a flow diagram of an illustrative embodiment thermalprotection process in accordance with the present invention;

FIG. 43 is a block diagram of an illustrative embodiment battery enableswitch apparatus in accordance with the present invention;

FIG. 44 is a flow diagram of a battery enable process.

FIG. 45 is a perspective view of the weigh frame and portions of thedeck of the patient support of FIG. 1, showing the illustrative head andfoot end siderails in raised positions;

FIG. 46 is a side elevational view of the weigh frame and portions ofthe deck of FIG. 45, showing the head and foot end siderails in theraised positions;

FIG. 47 is a view similar to FIG. 46, showing the head and foot endsiderail in lowered positions;

FIG. 48 is an exploded perspective view of the illustrative embodimenthead end siderail of the patient support of FIG. 1;

FIG. 49 is an exploded perspective view of a link of the head endsiderail and a retainer or latch;

FIG. 50 is a perspective view of the link of FIG. 49, with the coverremoved, illustrating a cord extending therethrough;

FIG. 51 is an exploded perspective view of the illustrative embodimentfoot end siderail of the patient support of FIG. 1;

FIG. 52 is a top plan view of the latch in a latched position;

FIG. 53 is a view similar to FIG. 52, showing the latch in an unlatchedposition;

FIG. 54 is a perspective view of the link of FIG. 49, showing pins ofthe latch extending out from the link;

FIG. 55 is a view similar to FIG. 54, showing the pins withdrawn intothe link;

FIG. 56 is an exploded perspective similar to FIG. 49, illustrating analternative embodiment latch;

FIG. 57 is a perspective view similar to FIG. 1, illustrating analternative embodiment patient support including alternative embodimentsof headboard, head end siderails, and foot pedal controls coupled to thedeck support;

FIG. 58 is a cross-sectional view taken along lines 58-58 in FIG. 57showing a gap defined between the deck and one of the foot end siderailsand the foot end siderail including a bump to narrow the gap;

FIG. 59 is an enlarged view of a portion of FIG. 57 showing theheadboard and one of the head end siderails cooperating to define a gaptherebetween and the headboard including a bump to narrow the gap nearthe top portion of the head end siderail;

FIG. 60 is an exploded perspective view of an illustrative embodimentrail member of the head end siderail;

FIG. 61 is a cross sectional view taken along line 61-61 of FIG. 46;

FIG. 62 is an enlarged view of a portion of FIG. 61, showing an O-ringseal positioned between a main body of head end siderail and a cover ofhead end siderail;

FIG. 63 is a partial side elevational view of an inner side of a coverof the rail member of the head end siderail of FIG. 60, showing acircuit board coupled to the cover and a cord extending from acontroller to the circuit board;

FIG. 64 is a side elevational view of an inner side of a main body ofthe rail member of the head end siderail of FIG. 60, showing the link ofFIG. 49 positioned adjacent the head end siderail and showing a cordextending through the link and head end siderail;

FIG. 65 is an exploded perspective view of a rail member of the foot endsiderail;

FIG. 66 is a cross sectional view taken along taken along line 66-66 ofFIG. 46;

FIG. 67 is an enlarged view of a portion of FIG. 66, showing an O-ringseal positioned between a main body of foot end siderail and a cover offoot end siderail;

FIG. 68 is a cross-sectional view taken along line 68-68 of FIG. 45,showing a controller coupled to the head end siderail;

FIG. 69 is an exploded perspective view of the controller of FIG. 68;

FIG. 70 is an exploded perspective view of a retainer or latch of thecontroller of FIG. 68;

FIG. 71 in exploded perspective view of an alternative embodimentretainer or latch for the controller of FIG. 68;

FIG. 72 is a perspective view of a shell of the controller of FIG. 68,showing a cord extending into the shell;

FIG. 73 is a side elevational view of a first interface panel;

FIG. 74 is a side elevational view of a second interface panel;

FIG. 75 is a side elevational view of a third interface panel;

FIG. 76 is a side elevational view of an illustrative embodiment footpedal control of the present invention, showing the foot of a caregiver(in phantom) positioned to step on the foot pedal control;

FIG. 77 is a cross sectional view taken along line 77-77 of FIG. 80,showing the foot pedal control in a raised position;

FIG. 78 is a view similar to FIG. 77, showing the foot pedal control ina lowered position;

FIG. 79 is an exploded perspective view of the foot pedal control ofFIG. 76;

FIG. 80 is a perspective view of the foot pedal control of FIG. 76;

FIG. 81 is an electrical schematic diagram of a sensor and associatedcircuitry for the foot pedal control of FIG. 76;

FIG. 82 is a perspective view of an alternative embodiment foot pedalcontrol of the present invention;

FIG. 83 is a partial perspective view of a further alternativeembodiment foot pedal control of the present invention;

FIG. 84 is a cross-sectional view taken along line 84-84 of FIG. 83,showing the foot pedal of FIG. 83 in a raised position;

FIG. 85 is a view similar to FIG. 84, showing the foot pedal of FIG. 83in a lowered position;

FIG. 86 is a perspective view of another alternative embodiment footpedal control of the present invention;

FIG. 87 is a cross-sectional view taken along line 87-87 of FIG. 86,showing the foot pedal of FIG. 86 in a raised position;

FIG. 88 is a view similar to FIG. 87, showing the foot pedal of FIG. 86in a lowered position;

FIG. 89 is a perspective view of another alternative embodiment footpedal control of the present invention;

FIG. 90 is a cross-sectional view taken along line 90-90 of FIG. 89,showing the foot pedal of FIG. 89 in a raised position;

FIG. 91 is a view similar to FIG. 90, showing the foot pedal of FIG. 89in a lowered position;

FIG. 92 is an exploded perspective view of an illustrative embodiment ofthe modular mattress assembly of the present invention;

FIG. 93 is a perspective view of a foot section of the mattress of FIG.92, illustrating a heel pressure relief sleeve received within a heelzone cavity, and with the outer cover, the shear liner, and the firebarrier removed for clarity;

FIG. 94 is a perspective view of the heel pressure relief sleeve of thepresent invention;

FIG. 95 is a perspective view of an alternative embodiment heel pressurerelief sleeve of the present invention;

FIG. 96 is a cross-sectional view taken along line 96-96 of FIG. 93illustrating the foot section in an extended position;

FIG. 97 is a cross-sectional view similar to that of FIG. 96illustrating the foot section in a retracted position;

FIG. 98 is a perspective view of the receiving base of the mattressassembly of FIG. 92;

FIG. 99 is a top plan view of the mounting substrate of the mattressassembly of FIG. 92;

FIG. 100 is a perspective view similar to that of FIG. 98, illustratingthe mounting substrate and the foot section securing substrate coupledthe receiving base;

FIG. 101 is a cross-sectional view taken along line 101-101 of FIG. 100illustrating the mounting substrate and the foot section securingsubstrate coupled to the base, and further illustrating a portion of thefoot section;

FIG. 102 is an end elevational view of the foam core of the mattressassembly of FIG. 92;

FIG. 103 is a perspective view of the turn assist bladder assembly ofthe mattress assembly of FIG. 92, illustrating the bladders in aninactive, deflated mode of operation;

FIG. 104 is a perspective view similar to that of FIG. 103 illustratingthe left turn assist bladder in an active, inflated mode of operation,and the right turn assist bladder in an inactive, deflated mode ofoperation;

FIG. 105 is an end elevation view of the upper bladder assembly of themattress assembly of FIG. 92;

FIG. 106 is a top plan view of the upper bladder assembly of FIG. 105;

FIG. 107 is a side elevational view of the upper bladder assembly ofFIG. 105;

FIG. 108 is a perspective view of the mattress assembly of FIG. 92 withthe outer cover, the sheer liner, and the fire barrier removed forclarity;

FIG. 109 is a cross-sectional view taken along line 109-109 of FIG. 108;

FIG. 110 is a detail perspective of the sheer liner applied to the headend of the mattress assembly of FIG. 92;

FIG. 111 is a bottom perspective view of the mattress assembly of FIG.92, illustrating the mattress anchors and the access port;

FIG. 112 is a side cross-sectional view, in partial schematic,illustrating the body section of the receiving base in a substantiallyplanar position;

FIG. 113 is a side cross-sectional view similar to FIG. 112,illustrating the body section of the receiving base with the basesection elevated relative to the seat section;

FIG. 114 is an end elevational view illustrating the upper bladderassembly in an active, inflated mode of operation;

FIG. 115 is a end elevational view similar to that of FIG. 114,illustrating the right turn assist bladder inflated for assisting in theturning of a patient supported on the mattress assembly;

FIG. 116 is a block diagram illustrating various pneumatic connectionsbetween the mattress and the air control system of the presentinvention;

FIG. 117 is a front elevational view of a manifold assembly of thepresent invention configured to supply a fluid to the air mattressassembly of FIG. 92 and supported by the articulating deck of thepatient support of FIG. 1;

FIG. 118 is a bottom elevational view of the manifold assembly of FIG.117;

FIG. 119 is a cross-sectional view taken along line 119-119 of FIG. 117,illustrating a normally-closed spring biased valve and a normally-openspring biased valve;

FIG. 120 is a detailed perspective view illustrating the manifoldreceiving fluid connector and the mating mattress fluid connector of thepresent invention;

FIG. 121 is a front elevational view of the mattress fluid connector ofFIG. 120;

FIG. 122 is a perspective view of a sealing gasket of the presentinvention for use with the manifold receiving fluid connector of FIG.120;

FIG. 123 is a cross-sectional view illustrating the sealing gasket ofFIG. 122 coupled intermediate the partition and the manifold receivingconnector;

FIG. 124 is a block diagram of an illustrative embodiment pressurecontrol system for controlling inflation of air bladders in accordancewith the present invention;

FIG. 125 is a flow diagram of an illustrative embodiment process forcontrolling inflation of air bladders in accordance with the presentinvention;

FIG. 126 is a flow diagram of an illustrative embodiment process forcontrolling operation of turn assist bladders in accordance with thepresent invention;

FIG. 127 is a flow diagram of an illustrative embodiment process formonitoring activity during the operation of turn assist bladders inaccordance with the present invention;

FIG. 128 is a flow diagram of an illustrative embodiment process forcontrolling inflation of air bladders in accordance with the presentinvention;

FIG. 129 is an upper perspective view of the deck and weigh frame of thealternative embodiment patient support of FIG. 57 showing the footsection in an extended position, the head section elevated relative tothe seat section, a partition of the head section with portions cutawayshowing a manifold assembly on a first side of the partition and amanifold connector on a second side of the partition, and patientsensors supported by the head section and the seat section;

FIG. 130 is an exploded perspective view of an illustrative embodimentof the modular mattress assembly of the present invention, with the topcover removed for clarity;

FIG. 131 is a perspective view of the modular mattress assembly of FIG.130, with the outer cover, the shear liner, and the fire barrier removedfor clarity;

FIG. 132 is a partially exploded perspective view of a foot section ofthe mattress assembly of FIG. 130, illustrating a heel pressure reliefbladder assembly received within a heel zone cavity, and with the outercover, the shear liner, and the fire barrier removed for clarity;

FIG. 133 is an end elevational view of the foot section of FIG. 132;

FIG. 134 is a top plan view of the foot section, the turn assist bladderassembly, and the mounting substrate of the mattress assembly of FIG.130, illustrating the routing of the fill tube and the sensor tube fromproximate a head end of the mattress assembly to the air bladders of theheel pressure relief bladder assembly;

FIG. 135 is a side elevational view of the partial mattress assembly ofFIG. 134;

FIG. 136 is a fragmentary view of the partial mattress assembly shown inFIG. 135;

FIG. 137 is a top plan view of the mounting substrate of the mattressassembly of FIG. 130;

FIG. 138 is a perspective view of the mounting substrate and the footsection securing substrate coupled the receiving base of the mattressassembly of FIG. 130;

FIG. 139 is a top plan view of the turn assist bladder assembly and themounting substrate of the mattress assembly of FIG. 130, illustratingthe routing of the fill tubes and the sensor tubes from proximate a headend of the mattress assembly to the air bladders of the turn assistbladder assembly;

FIG. 140 is a cross-sectional view taken along line 140-140 of FIG. 131,illustrating the left turn assist bladder and the right turn assistbladder in inactive, deflated modes of operation;

FIG. 141 is a cross-sectional view similar to that of FIG. 140illustrating the right turn assist bladder in an active, inflated modeof operation, and the left turn assist bladder in an inactive, deflatedmode of operation;

FIG. 142 is an end elevation view of an air bladder of the upper bladderassembly of the mattress assembly of FIG. 130;

FIG. 143 is a top plan view of the upper bladder assembly of themattress assembly of FIG. 130;

FIG. 144 is a top plan view of the head zone of the upper bladderassembly and the mounting substrate of the mattress assembly of FIG.130, illustrating the routing of the fill tube and the sensor tube fromproximate a head end of the mattress assembly to the air bladders of thehead zone, with the mounting substrate disconnected from the airbladders for illustrative purposes;

FIG. 145 is a top plan view of the seat zone of the upper bladderassembly and the mounting substrate of the mattress assembly of FIG.130, illustrating the routing of the fill tube and the sensor tube fromproximate a head end of the mattress assembly to the air bladders of theseat zone, with the mounting substrate disconnected from the airbladders for illustrative purposes;

FIG. 146 is a bottom perspective view of the mattress assembly of FIG.130, illustrating the mattress anchors and the access port;

FIG. 147 is a block diagram illustrating various pneumatic connectionsbetween the mattress air zones and the air control system of the presentinvention;

FIG. 148 is a detailed perspective view of illustrative embodimentmanifold fluid connector and mattress fluid connector of the presentinvention;

FIG. 149 is a rear elevational view of the manifold fluid connector ofFIG. 148, with the manifold and portions of the partition removed forclarity, illustrating a mattress sensor of the present invention;

FIG. 150 is a front elevational view of the manifold fluid connector ofFIG. 149;

FIG. 151 is a cross-sectional view taken along line 151-151 of FIG. 150,illustrating the connection between the manifold fluid connector and themattress fluid connector of the present invention;

FIG. 152 is an electrical diagram of the mattress sensor and associatedcircuitry for the manifold fluid connector of FIG. 148;

FIG. 153 is a block diagram of an illustrative embodiment valve sensorconfigured to detect the type of valve for controlling inflation of airzones of the mattress assembly of FIG. 130;

FIG. 154 is a flow diagram of an illustrative embodiment process foroperating the mattress sensor of FIG. 149;

FIG. 155 is a flow diagram of an illustrative embodiment process forcontrolling inflation of air zones of the mattress assembly of FIG. 130;

FIG. 156 is a block diagram of an illustrative embodiment system fordetermining the weight of a patient supported by the deck of the patientsupport of FIG. 57;

FIG. 157 is a flow diagram of an illustrative process for determiningthe weight of a patient supported by the deck of the patient support ofFIG. 57;

FIG. 158 is a continuation of the flow diagram of FIG. 157;

FIG. 159 is a flow diagram of an illustrative embodiment process forcontrolling operation of turn assist bladders of the mattress assemblyof FIG. 130;

FIG. 160 is a flow diagram of an illustrative embodiment process forboosting pressure of seat air zone in response to elevation of the headair zone of the air mattress;

FIG. 161 is a flow diagram of an illustrative embodiment process forboosting pressure of seat air zone in response to a patient sitting up;

FIG. 162 is a perspective view of an illustrative pump of the patientsupport of FIG. 1, showing the pump supported by a strut of theintermediate frame;

FIG. 163 is a exploded perspective view of the pump of FIG. 162;

FIG. 164 is a cross-sectional view taken along line 164-164 of FIG. 162,showing the pump coupled to the strut;

FIG. 165 is a cross-sectional view taken along line 165-165 of FIG. 162,showing a filter and muffler unit of the pump;

FIG. 166 is a cross-sectional view of a resilient foot of the pump ofFIG. 162;

FIG. 167 is a view similar to FIG. 166, showing an alternativeembodiment resilient foot;

FIG. 168 is a perspective view of an alternative embodiment air pump,showing the air pump supported by the strut of the weigh frame;

FIG. 169 is an exploded perspective view of the air pump of FIG. 168;

FIG. 170 is a cross-sectional view taken along line 170-170 of FIG. 168showing the air pump coupled to the strut;

FIG. 171 is a cross-sectional view taken along line 171-171 of FIG. 168showing a filter and muffler unit of the air pump;

FIG. 172 is another perspective view of the air pump of FIG. 168; and

FIG. 173 is a cross-sectional view taken along line 173-173 of FIG. 172.

DETAILED DESCRIPTION OF THE DRAWINGS

A patient support 10 according to the present disclosure is shown inFIG. 1. Patient support 10 includes a frame 12, a mattress 14 supportedby frame 12, a headboard 16, a footboard 18, a pair of head endsiderails 20, and a pair of foot end siderails 22. Frame 12 includes adeck support 24 and a deck 26 supporting mattress 14 and extendingbetween opposing head and foot ends 25 and 27. Deck support 24 includesa base frame 28 supported on the floor 29 by a plurality of casterwheels 30, an intermediate frame 32, a pair of lift arms 34 configuredto raise and lower intermediate frame 32 relative to base frame 28, anda weigh frame 36 supported by intermediate frame 32. Deck 26 issupported by weigh frame 36 and is configured to articulate between aplurality of positions. As illustrated in FIGS. 1 and 3-7, deck 26includes a head section 38 pivotably coupled to weigh frame 32, a seatsection 40 pivotably coupled to weigh frame 32, and an adjustable lengthleg or foot section 42 pivotably coupled to seat section 40.

Head end siderails 20 are coupled to head section 38 and may be movedbetween raised and lowered positions. Foot end siderails 22 are coupledto weigh frame 32 and may also be moved between raised and loweredpositions.

A control system 44 is provided to control various functions of patientsupport 10. Control system 44 and the remainder of patient support 10are powered by an AC plug connection 45 to a building outlet or abattery 46 supported by frame 12.

Control system 44 operates and monitors a plurality of linear actuators48 provided to extend and retract adjustable length leg section 42, tomove intermediate frame 32 relative to base frame 28, to move headsection 38 relative to weigh frame 32, to move seat section 40 relativeto weigh frame 32, and to move leg section 42 relative to seat section40.

Control system 44 includes a plurality of input devices including adetachable siderail controller 50 configured to removably couple to anyof head and foot end siderails 20, 22, a first pair of permanentsiderail controllers 52 coupled to head end siderails 20, a second pairof permanent siderail controllers 54 pivotably coupled to head endsiderails 20, and a pair of foot pedal controls 56 coupled to base frame28.

Control system 44 also includes an obstacle detection device 58illustratively coupled to base frame 28 to detect possible clearanceissues between intermediate frame 32 and base frame 28. Control system44 further includes a plurality of actuator position detectors or motorsensor (as discussed below) provided with each of the plurality ofactuators 48. A plurality of load cells (discussed below) are alsoprovided between weigh frame 36 and intermediate frame 32 to providesignals that indicate of the weight supported by intermediate frame 32.Control system 44 uses these signals to determine the weight of apatient positioned on mattress 14. Additionally, control system 44includes a plurality of siderail position detectors or sensors 60configured to provide signals indicative of the position of siderails20, 22.

Control system 44 is configured to control a pump 64 in fluidcommunication with a manifold 62 supported on head section 38 of deck26. Manifold 62 is in fluid communication with mattress 14 to regulatethe flow of air to and from mattress 14. Mattress 14 includes an outercover 66 and a first pair of connectors 68 coupled to outer cover 66. Asecond pair of connectors 70 is provided on head section 38 of deck 26that align and couple with first pair of connectors 68.

Deck Support

As previously mentioned and as shown in FIG. 1, deck support 24 includesa base frame 28 supported on the floor 29 by a plurality of casterwheels or caster devices 30, an intermediate frame 32, a pair of liftarms 34 configured to raise and lower intermediate frame 32 relative tobase frame 28, and a weigh frame 36 supported by intermediate frame 32.Linear actuators 48 a and 48 b, shown in FIG. 2, provide power toactuate lift arms 34 and in turn to raise and lower intermediate frame32 relative to base frame 28.

As explained in more detail below, lift arms 34 and linear actuators 48a and 48 b, commonly referred to as a hi/low mechanism, are configuredto position deck support 24 in at least the following positions: araised or upper position wherein intermediate frame 32 and weigh frame36 are above base frame 28 (FIGS. 1-6); a first lowered position whereinat least a portion of intermediate frame 32 and/or weigh frame 36 isnested within base frame 28 (FIG. 7); a Trendelenburg position wherein ahead end 102 of intermediate frame 32 is lower than a foot end 104 ofintermediate frame 32 (FIG. 8); and a Reverse Trendelenburg positionwherein foot end 104 of intermediate frame 32 is lower than head end 102of intermediate frame 32 (FIGS. 9, 10 and 11). One skilled in the artwill appreciate that the positions shown in FIGS. 1-11 are exemplarypositions and that intermediate frame 32 is positionable in a widevariety of positions relative to base frame 28.

Lift Arms

Referring to FIG. 2, lift arms 34 include a pair of head links 106pivotably coupled to head end 102 of intermediate frame 32 and slidablyand pivotably coupled to base frame 28, a pair of foot links 108pivotably coupled to foot end 104 of intermediate frame 32 and slidablyand pivotably coupled to base frame 28, and a pair of guide links 110pivotably coupled to respective foot links 108 and pivotably coupled tobase frame 28 at a fixed pivot point. Alternatively, the guide links 110are pivotably coupled to the respective foot links 108, and theintermediate frame 32, or pivotably coupled to the respective head links106 and the base frame 28, or pivotably coupled to the respective headlinks 106 and the intermediate frame 32. In further alternativeembodiments, two sets of guide links 110 are provided, one set pivotablycoupled to the foot links 108 and either the base frame 28 or theintermediate frame 32 and one set coupled to the head links 106 andeither the base frame 28 or the intermediate frame 32.

Each head link 106 is slidably coupled to base frame 28 and pivotablycoupled to intermediate frame 32. Alternatively, each of the head links106 is slidably coupled to either the base frame 28 or the intermediateframe 32. As illustratively shown in FIG. 2, each head link 106 isslidably and pivotably coupled to base frame 28 at pivot 113 by a slideblock 111. Slide block 111 is pivotably coupled to a lower portion 112of head link 106 and slidably received in a guide 114 coupled to baseframe 28. In one embodiment, the material used for the slide blocks 111and the guides 114 and the surface characteristics of the slide blocks111 and the guides 114 are chosen to reduce the coefficient of frictionbetween the slide blocks 111 and the guides 114.

Guide 114 includes an upper channel 116 and a lower channel 118 whichdefine two directions of travel 120 and 121 for slide block 111. Upperchannel 116 and lower channel 118 are further configured to restrict themovement of slide block 111 in any direction other than directions oftravel 120 and 121. Slide blocks 111 are preferred because they arecapable of spreading the load of intermediate frame 32, deck 26 andother patient support components over a larger surface area than othertypes of couplers. Alternative methods of coupling the head links 106 tothe base frame 28 can be used provided that the lower portion of thehead links 106 can pivot relative to the base frame 28 and can movealong the directions of travel 120, 121. Examples include a roller, aplurality of rollers, or interlocking members.

Illustratively, an upper end 122 of each head link 106 is pivotablycoupled to intermediate frame 32 through a cross link 124.Alternatively, the head links 106 are directly pivotably coupled to theintermediate frame 32. In a further alternative, the head links 106 arepivotably coupled to the base frame 28 and slidably and pivotablycoupled to the intermediate frame 32.

Cross link 124 extends between each head link 106 and is rigidly coupledto each head link 106. As such, cross link 124 coordinates thesimultaneous movement of head links 106. Cross link 124 is receivedthrough openings (not shown) formed in intermediate frame 32 and ispivotable relative to intermediate frame 32. In one embodiment, abearing or other means is used to increase the ease by which cross link124 pivots relative to intermediate frame 32.

Each foot link 108, is slidably and pivotably coupled to base frame 28.Illustratively each foot link 108 is coupled to base frame 28 at pivot126 by slide block 128 which is pivotably coupled to a lower portion 130of foot link 108 and slidably received in a guide 132 coupled to baseframe 28. Guide 132 and slide block 128 are generally identical to guide114 and slide block 111 discussed in conjunction with head links 106. Assuch, guide 132 is configured to restrict the movement of slide block128 in any direction other than directions of travel 120 and 121.Alternative methods of coupling the foot links 108 to the base frame 28can be used provided that the lower portion of the foot links 108 canpivot relative to the base frame 28 and can move along the directions oftravel 120, 121. Examples include a roller, a plurality of rollers, orinterlocking members.

An upper end 134 of each foot link 108 is pivotably coupled tointermediate frame 32 through a cross link 136. Alternatively, the footlinks 108 are directly pivotably coupled to the intermediate frame 32.Cross link 136 is generally identical to cross link 124 and cooperateswith intermediate frame 32 and foot links 108 in the same manner ascross link 124 with intermediate frame 32 and head links 106.Alternatively, the upper end 134 of each foot link 108 is slidably andpivotably coupled to the intermediate frame 32 and pivotably coupled tothe base frame 28.

Guide links 110 restrict the motion of foot links 108 such that thepivot point 138 between foot links 108 and intermediate frame 32 isrestrained to move vertically without moving horizontally. Thisrestriction prevents horizontal movement of intermediate frame 32relative to base frame 28 during the raising and lowering ofintermediate frame 32. This restrained movement prevents intermediateframe 32 from moving through an arc while moving between the upperposition of FIG. 2 and the lower position of FIG. 7 so that intermediateframe 32 can be raised and lowered without requiring additional hospitalroom for clearance.

It will be appreciated that, in order for guide links 110 to perform therestriction function, the distance between pivots 140 (pivot betweenguide link 110 and foot link 108) and 142 (pivot between guide links 110and base frame 28) of guide links 110 is one half the distance betweenpivot 126 (pivot between slide blocks 128 and base frame 28) and pivot138 (pivot between upper ends 134 of foot links 108 and intermediateframe 32). Further, each guide link 110 is pivotably coupled to therespective foot link 108 at pivot 140 that is one half the distancebetween pivot 126 of the associated slide block 128 and pivot 138 of theupper end of the respective foot link 108. Thus, the distance betweenupper pivot 140 of each guide link 110 and the lower pivot 142 of eachguide link 110 is equal to the distance between upper pivot 140 of eachguide link 110 and upper pivot 138 of each foot link 108. As a result ofthis link geometry, upper pivots 138 of foot links 108 are maintained invertical alignment with lower pivot 142 of guide links 110 during theraising and lowering of intermediate frame 32 relative to base frame 28.

Linear Actuators

As stated earlier, linear actuators 48 a and 48 b provide power toactuate lift arms 34 and in turn to raise and lower intermediate frame32 relative to base frame 28. Linear actuator 48 a is coupled to andactuates head links 106 and linear actuator 48 b is coupled to andactuates foot links 108. As such, foot end 104 and head end 102 ofintermediate frame 32 can be raised and lowered independent of oneanother. Alternatively, head links 106 and foot links 108 of the deckingsystem are coupled together such that a single actuator raises andlowers the head end 102 and the foot end 104 of the intermediate frame32 at the same time.

Illustratively, a first end 146 of linear actuator 48 a is coupled tohead links 106 through an extension link 148 that is rigidly coupled tocross link 124 which, in turn, is rigidly coupled to head links 106. Asshown in FIG. 2, first end 146 is pivotably coupled to extension link148 through a fastener or pivot pin 150. A second end 152 of linearactuator 48 a is coupled to a first bracket 154 which is rigidly coupledto intermediate frame 32. As shown in FIG. 2, second end 152 ispivotably coupled to first bracket 154 through a fastener or pivot pin156.

Similarly, a first end 158 of linear actuator 48 b is coupled to footlinks 108 through an extension link 160 that is rigidly coupled to crosslink 136 which, in turn, is rigidly coupled to foot links 108. As shownin FIG. 2, first end 158 is pivotably coupled to extension link 160through a fastener or pivot pin 162. A second end 164 of linear actuator48 b is coupled to a second bracket 166 which is rigidly coupled tointermediate frame 32. Second end 164 is pivotably coupled to secondbracket 166 through a fastener or pivot pin 168.

Each actuator 48 a and 48 b is preferably an electric linear actuatorhaving respective cylinder bodies 170, cylinder rods 172, and motors 604that operate to extend and retract cylinder rods 172 relative tocylinder bodies 170. As such, actuators 48 a and 48 b have variablelengths and therefore adjust the distance between pivot pins 150 and 156and pivot pins 162 and 168, respectively. In one illustrativeembodiment, actuators 48 a and 48 b are Linak actuators, Model No. LA34,available from LINAK U.S. Inc. located at 2200 Stanley Gault Parkway,Louisville Ky. 40223. Further, actuators 48 c, 48 d, 48 e and 48 f arealso illustratively electric linear actuators, and in one embodiment arealso Linak actuators. More particularly, actuator 48 c is illustrativelya Linak actuator, Model No. LA34 and actuators 48 d-48 f areillustratively Linak actuators, Model No. LA31. In alternativeembodiments, all of the actuators 48 or any one or more of the actuatorsare other types of electric actuators, pneumatic actuators, hydraulicactuators, mechanical actuators, link systems or other components knownto those of ordinary skill in the art for coordinating movement ofcomponents relative to one another.

The actuation of either actuator 48 a or 48 b alone causes either therespective head end 102 of intermediate frame 32 or the respective footend 104 of intermediate frame 32 to be raised or lowered relative tobase frame 28. Referring to FIG. 2, head end 102 of intermediate frame32 is lowered relative to base frame by the retraction of cylinder rod172 a of actuator 48 a. As cylinder rod 172 a of actuator 48 a isretracted, the distance between pivot pins 150 and 156 is reduced. Thisreduction in pivot spacing causes extension link 148 to move towardfirst bracket 154 which in turn causes cross link 124 and head links 106to rotate in direction 176 about pivot 126. Since lower portions 112 ofhead links 106 are restrained to move only in directions of travel 120and 121 of guide 114, the rotation of head links 106 in direction 176causes lower portions 112 of head links 106 to travel in direction 120.As a result upper ends 122 of head links 106 are lowered relative tobase frame 28 and therefore head end 102 of intermediate frame 32 islowered relative to base frame 28.

Head end 102 of intermediate frame 32 is raised relative to base frame28 by the extension of cylinder rod 172 of actuator 48 a. As cylinderrod 172 of actuator 48 a is extended the distance between pivot pins 150and 156 is increased. This increase in pivot spacing causes extensionlink 148 to move away from first bracket 154 which, in turn, causescross link 124 and head links 106 to rotate in a direction 178 counterto direction 176 about pivot 126. The rotation of head links 106 indirection 178 counter to direction 176 causes lower portions 112 of headlinks 106 to travel in direction 121. As a result, upper ends 122 ofhead links 106 are raised relative to base frame 28 and therefore, headend 102 of intermediate frame 32 is raised relative to base frame 28.

Foot end 104 of intermediate frame 32 is lowered relative to base frame28 by the retraction of cylinder rod 172 b of actuator 48 b. As cylinderrod 172 b of actuator 48 b is retracted the distance between pivot pins162 and 168 is reduced. This reduction in pivot spacing causes extensionlink 160 to move toward second bracket 166 which, in turn, causes crosslink 136 and foot links 108 to rotate in direction 180 about pivot 138.Since lower portions 130 of foot links 108 are restrained to move onlyin directions of travel 120 and 121 of guide 132, the rotation of footlinks 108 in direction 180 causes lower portions 130 of foot links 108to travel in direction 121. As a result, upper ends 134 of foot links108 are lowered relative to base frame 28 and therefore, foot end 104 ofintermediate frame 32 is lowered relative to base frame 28.

Foot end 104 of intermediate frame 32 is raised relative to base frame28 by the extension of cylinder rod 172 b of actuator 48 b. As cylinderrod 172 b of actuator 48 b is extended, the distance between pivots 162and 168 is increased. This increase in pivot spacing causes extensionlink 160 to move away from second bracket 166 which, in turn, causescross link 136 and foot links 108 to rotate in a direction 182 counterto direction 180 about pivot 138. The rotation of foot links 108 indirection 182 counter to direction 180 causes lower portions 130 of footlinks 108 to travel in direction 120. As a result, upper ends 134 offoot links 108 are raised relative to base frame 28 and therefore, footend 104 of intermediate frame 32 is raised relative to base frame 28.

The simultaneous actuation of actuators 48 a and 48 b causes both headend 102 and foot end 104 of intermediate frame 32 to raise or lowerrelative to base frame 28. As shown in FIG. 2, the simultaneousextension of both actuators 48 a and 48 b causes both head end 102 andfoot end 104 of intermediate frame 32 to raise relative to base frame 28and intermediate frame 32 to be spaced apart from base frame 28. Thesimultaneous retraction of both actuators 48 a and 48 b causes both headend 102 and foot end 104 of intermediate frame 32 to lower relative tobase frame 28. It should be appreciated that actuator 48 a can beextended while actuator 48 b is retracted, resulting in head end 102being raised while foot end 104 is lowered, or that actuator 48 a can beretracted while actuator 48 b is extended, resulting in head end 102being lowered while foot end 104 is raised.

Further, in an alternative embodiment the direction of one of theactuators 48 a, 48 b is reversed such that to raise the intermediateframe 32 relative to the base frame 28 a first of the two actuators 48a, 48 b is extended and the second actuator 48 b, 48 a is retracted.Further, to lower the intermediate frame 32 relative to the base frame28 the second actuator 48 b, 48 a is extended and the first actuator 48a, 48 b is retracted.

Referring further to FIG. 2, deck support 24 is in an upper positionwhen actuators 48 a and 48 b are both extended. Deck support 24 is movedfrom the upper position of FIG. 2 to the Trendelenburg position of FIG.8 by retracting actuator 48 a and thus lowering head end 102 ofintermediate frame 32. Deck support 24 is returned to the upper positionof FIG. 2 by extending actuator 48 a back to its prior length. Decksupport 24 is moved from the upper position of FIG. 2 to the ReverseTrendelenburg position of FIGS. 9 and 10 by retracting actuator 48 b andthus lowering foot end 104. Deck support 24 is returned to the upperposition of FIG. 2 by extending actuator 48 b back to its prior length.

Deck support 24 is moved from the upper position of FIG. 2 to thelowered position of FIG. 7 by simultaneously retracting actuators 48 aand 48 b and thus lowering both head end 102 and foot end 104 ofintermediate frame 32. Deck support 24 is moved back to the upperposition of FIG. 2 from the lowered position of FIG. 7 by simultaneouslyextending actuators 48 a and 48 b. It should be appreciated thatactuators 48 a and 48 b can place the patient support 10 in a variety ofpositions from any starting position and that the upper position shownin FIG. 2 is simply a reference starting position used to explain theoperation of the deck support.

Since actuators 48 a and 48 b retract and extend at substantially thesame rates, the simultaneous retraction of actuators 48 a and 48 bcauses intermediate frame 32 to be maintained in a generally horizontalposition as it is vertically transitioned from the upper position ofFIG. 2 to the lowered position of FIG. 7 and then raised back again tothe upper position of FIG. 2. Further, control system 44 is configuredto control each actuator 48 a-f and therefore can independently controlthe speed of each actuator 48 a-f. Also, as discussed above, guide links110 are configured to generally maintain the vertical alignment ofintermediate frame 32 and base frame 28 such that intermediate frame 32does not “swing” outwardly or inwardly relative to base frame 28 asintermediate frame 32 is transitioned between various positions.

One of the purposes of intermediate frame 32 being configured to raiseand lower relative to base frame 28 is to aid in the ingress of apatient to and egress of a patient from patient support 10. To allowintermediate frame 32 to lower further and thus provide additionalassistance in the ingress to and egress of the patient from patientsupport 10, patient support 10 is configured to provide a loweredposition, as shown in FIG. 7, wherein portions of deck support 24 nestwithin other portions of deck support 24. Thus, an overall height 183 ofdeck support 24 and, in turn, an overall height of mattress 14 isreduced. Further, by placing patient support 10 in the lowered positionof FIG. 7, the possibility of patient injury due to accidental egressfrom patient support 10 is reduced due to the fact that the patient iscloser to the floor 29 than in conventional patient supports.

Nesting Frames

As shown in FIGS. 7 and 8, portions of intermediate frame 32 areconfigured to nest within base frame 28 and/or extend below base frame28 when intermediate frame is in the lowered position. Alternatively,the base frame 28 can be configured to nest within the intermediateframe 32 when the intermediate frame 32 is in the lowered position. Asshown in FIGS. 2, 7 and 8, longitudinally-extending members 184, 186 ofintermediate frame 32 define a first outer width 188 of intermediateframe 32 that is less than an inner width 190 defined by longitudinallyextending members 192, 194 of base frame 28 and lifting arms 34.Further, an outer length 195 of intermediate frame 32 is less than aninner length 197 of base frame 28 and lifting arms 34, illustrativelyshown as the separation between cross link 185, shown in FIGS. 2 and 8,of head links 106 and cross link 187 of foot links 108. As such, asintermediate frame 32 is lowered to the lowered position, portions ofintermediate frame 32 are received within an interior region 196 definedby base frame 28 and lifting arms 34, thereby reducing overall height183 of deck support 24.

It should be noted that when deck support 24 is in the lowered position,head links 106, foot links 108 and guide links 110 are rotated beyondhorizontal, such that pivots 126, 138, 140 are generally lower thanpivots 142, 143, 144. In one embodiment, head links 106, foot links 108and guide links 110 are generally rotated from approximately 80° abovehorizontal in the upper position of FIG. 2 to approximately 10° belowhorizontal in the lowered position of FIG. 7. As shown in FIG. 2,intermediate frame 32 includes a plurality of gussets 208 which eachinclude a stop surface 210. Stop surface 210 is configured to contactand rest upon foot links 104 and head links 106, respectively, whenintermediate frame 32 is fully lowered. Stop surfaces 210 are configuredto prevent other portions of patient support 10, such as siderails 20,22, from contacting base frame 28. Alternatively, the stop surface 210is configured to contact and rest upon the base frame 28.

It is further contemplated that portions of weigh frame 36 areconfigured to nest within base frame 28 when intermediate frame 32 is inthe lowered position. Longitudinally extending members 198, 200, shownin FIGS. 3, 4 and 13, of weigh frame 36 define an outer width 202 ofweigh frame 36 that may be less than inner width 190 of base frame 28and lifting arms 34 (FIG. 7). Further, an outer length 204 of weighframe 36 may be less than inner length 197 of base frame 28 and liftingarms 34. As such, as intermediate frame 32 is lowered to the loweredposition, portions of weigh frame 36 as well as intermediate frame 32may nest within or extend below base frame 28 thereby further reducingoverall height 183 of deck support 24.

Weigh Frame

As noted above, intermediate frame 32 is coupled to weigh frame 36. Asshown in FIGS. 13 and 14, weigh frame 36 includes longitudinallyextending members 198, 200 and transversely extending members 211, 213.Load cells 220, 222, 224, 226 are coupled to a respective end oflongitudinally extending members 198, 200.

Referring further to FIG. 14, load cell 226 is shown. The descriptionbelow of load cell 226 is descriptive of all of load cells 220, 222,224, 226 unless specifically noted otherwise. Load cell 226 includes aload member, load beam, or cell block (hereinafter “cell block 221”)that is mounted at one of the four corners of the weigh frame 36.Conventional strain gages (not shown) are included in load cell 226 andare coupled to cell block 221. The strain gages operate in aconventional manner to provide an indication of the load supported byload cell 226. That is, a known input voltage is applied to input leads(not shown) coupled to the strain gages and, as cell blocks 221 deflectdue to the application of a load, the resistance of the strain gageschanges resulting in a change in an output signal generated on outputleads (not shown) coupled to the strain gages. In the illustrativeembodiment, the input and output leads are bundled together in a cable(not shown) that is routed between load cell 226 and conventional signalconditioning circuitry (not shown).

Block 221 is coupled to a mounting bar 223 of weigh frame 36 by suitablefasteners, such as bolts (not shown). Mounting bar 223 and block 221 arereceived in the interior region of weigh frame members 198, 200 as shownbest in FIG. 14. A stud 225 is coupled to block 221 and includes asocket portion 227 and a ball portion 228. Socket portion 227 isconfigured to capture ball portion 228 and to allow ball portion 228 torotate relative to socket portion 227.

Load cells 220, 222, 224, 226 are further configured to be coupled totransversely extending members 215, 217 of intermediate frame 32, shownin FIG. 2. As such weigh frame 36 is coupled to intermediate frame 32and supported by load cells 220, 222, 224, 226. Referring to FIGS. 2, 3and 15, a stud 229 is fastened to each opposing end of transverselyextending members 215 and 217 of intermediate frame 32 and is configuredto be received by ball portion 228 respective of load cells 220, 222,224, 226. As such, studs 229 and ball portions 228 couple weigh frame 36to intermediate frame 32.

The weight of weigh frame 36 and anything supported by weigh frame 36,such as deck 26, mattress 14, and a patient, is transmitted to loadcells 220, 222, 224, 226. This weight deflects or otherwise changes acharacteristic of load cells 220, 222, 224, 226 that is detected todetermine the total weight supported thereby. By subtracting a knownweight of weigh frame 36, deck 26, mattress 14 and any other bedcomponents supported on weigh frame 36, the weight of the patientpositioned on patient support 10 can be determined. Additionaldescription of illustrative load cells and methods for determining apatient's weight, position in the bed, and other indications provided byload cells is provided in U.S. patent application Ser. No. 09/669,707,filed Sep. 26, 2000, titled Load Cell Apparatus, to Mobley et al., thedisclosure of which is expressly incorporated by reference herein.According to alternative illustrative embodiments of the presentdisclosure, other configurations and methods of using load cells orother devices to determine a patient's weight or other informationrelated to the patient known to those of ordinary skill in the art areprovided herein.

Mattress Deck

As shown in FIGS. 3-5 and as previously mentioned, deck 26 is coupled toweigh frame 36 and includes several sections 38, 40, 42 that areconfigured to articulate between a plurality of positions. Head section38 is positioned adjacent headboard 16 (FIG. 1) and is pivotably coupledto weigh frame 36. In the illustrated embodiment as shown in FIGS. 16and 18, a first end 231 of head section 38 is pivotably coupled toupwardly extending flanges 230 of weigh frame 36 such that head section38 is rotatable about a pivot 232. Head section 38 is further coupled toactuator 48 c. In the illustrated embodiment actuator 48 c is pivotablycoupled to a downwardly extending bracket 233 of head section 38 and toa bracket 234 of weigh frame 36. Actuator 48 c is configured to raise asecond end 235 of head section 38. As such, second end 235 of headsection 38 can be raised or lowered relative to first end 231, by theextension or retraction of the length of cylinder 172 c of actuator 48c.

Seat section 40 is positioned adjacent head section 38 and is pivotablycoupled to weigh frame 36. In the illustrated embodiment as shown inFIGS. 16 and 18, a first end 236 of seat section 40 is pivotably coupledto flanges 230 of weigh frame 36 such that seat section 40 is rotatableabout a pivot 237. Seat section 40 is further coupled to actuator 48 d.In the illustrated embodiment, actuator 48 d is pivotably coupled to adownwardly extending bracket 238 of seat section 40 and to bracket 234of weigh frame 36. Actuator 48 d is configured to raise a second end 256of seat section 40. As such, second end 239 of seat section 40 may beraised or lowered relative to first end 236, by the extension orretraction of the length of cylinder 172 d of actuator 48 d.

Leg or foot section 42 is positioned adjacent seat section 40 and ispivotably coupled to seat section 40. In the illustrated embodiment asshown in FIGS. 16 and 18, second end 239 of seat section 40 is pivotablycoupled to a first end 244 of leg section 42 such that leg section 42 isrotatable about a pivot 241. Leg section 42 is further coupled toactuator 48 e. In the illustrated embodiment, actuator 48 e is slidablycoupled to a bracket 246 of leg section 42 and is pivotably coupled to abracket 248 of weigh frame 36. Actuator 48 e is configured to raise asecond end 250 of leg section 42. As such, second end 250 of leg section42 can be raised or lowered relative to first end 244, by the extensionor retraction of the length of cylinder 172 e of actuator 48 e.

Deck 26 is configured to support mattress 14. As shown in FIG. 16, headsection 38 and seat section 40 each includes angled side walls 260 a,260 b and 262 a, 262 b, respectively. Further, head section 38 and seatsection 40 each includes substantially flat lower deck portions, floorsor walls 264 and 266 connected to side walls 260 a, 260 b and 262 a, 262b, respectively. Angled side walls 260 a, 260 b and floor 264 and angledside walls 262 a, 262 b and floor 266 each cooperate to define a supportsurface for a portion of mattress 14. As shown in FIG. 16, the angledwalls 260 a, 260 b and 262 a, 262 b are oriented to form obtuse angleswith their respective floors 264 and 266. In one illustrativeembodiment, the angle formed is approximately 135 degrees. According toalternative embodiments of the present disclosure, the obtuse anglesbetween the side walls and the floor may range from slightly more than90 degrees to slightly less than 180 degrees. According to otheralternative embodiments of the present disclosure, the angles are rightangles or acute angles.

The lowered central portion, generally corresponding to floors 264 and266 of head section 38 and seat section 40, respectively, provides amplespace for mattress 14 to be positioned. By having a lowered centralportion, the pivot of a patient's hip when the patient is positioned onmattress 14 is more in line with pivots 232, 237 of head section 38 andseat section 40 and provides ample space to provide a mattress 14 thatprovides adequate support for the patient. In one illustrativeembodiment, the position of the pivot of the hip of the patient is abouttwo inches above the pivots 232, 237 of the head and seat sections 38and 40 of the deck 26. In another illustrative embodiment, the positionof the pivot of the hip of the patient is generally in line with thepivots 232, 237 of the head and seat sections 38 and 40 of the deck 26.By minimizing the distance between the pivot of the patient's hip andthe pivots 232, 237 of the head and seat sections 38 and 40, the amountof shear exerted against the patient is reduced as either the head orseat 38, 40 section is raised or lowered. By reducing the amount ofshear exerted against the patient, the possibility of the patientexperiencing skin breakdown is reduced.

As further shown in FIG. 16, head section 38 and seat section 40 furtherhave tapered adjacent end portions 268, 269 providing clearancetherebetween during titling of head section 38 or during tilting of seatsection 40.

In one illustrative embodiment, as previously described, the distancebetween the pivot of a patient's hip and pivots 232, 237 is about twoinches. Referring to FIG. 19, this translates into about a two inchthick section 270 of mattress 14 at the edge of the deck 26. Thethickness of the mattress 14 at the edge of the deck 26, illustrativelyabout two inches, provides needed support for the lateral transfer ofthe patient into and out of patient support 10. Further, the thicknessof the mattress 14 at the edge of the deck 26 provides a grip 271 forthe patient to grasp to aid in the egress from patient support 10. Inone embodiment the thickness of grip 271 is about two inches.

Head Section

Referring again to FIG. 16, head section 38 further includes a partition272 located proximate to second end 235. A generally vertical wall 274and a generally horizontal wall 275 form partition 272. In alternativeembodiments, vertical wall 274 may be contoured or sloped at any anglerelative to horizontal wall 275. On a mattress side of partition 272,first and second manifold receiving connectors 70 are coupled to wall272.

On the side opposite the mattress side, or manifold side of partition272, manifold 62 is coupled to partition 272. Referring to FIGS. 16 and18, a cover 282 is provided to enclose the manifold side of partition272. Cover 282 is coupled to the remainder of head section 38 byfasteners, such as snaps, screws, hook and loop fasteners, hinges,magnets, or other suitable fasteners. In one embodiment, a noise barrier(not shown) is positioned between the cover 282 and the remainder of thedeck 26. An illustrative noise barrier is formed from conventional foam.

As explained in more detail herein, first and second manifold receivingconnectors 70 are configured to be coupled to mattress connecters 68,which are in fluid communication with mattress 14. Manifold 62 isconfigured to be in fluid communication with pump 64. As such, mattress14 may be easily assembled to patient support 10 by simply couplingfirst and second manifold receiving connectors 70 with connectors 68. Inalternate embodiments, a single or three or more manifold receivingconnectors are coupled to the partition.

In one embodiment, at least vertical wall 274 of partition 272 isremovably coupled to head section 38. Vertical wall 274 is assembledwith manifold 62 and first and second manifold receiving connectors 70to form a sub-assembly. The sub-assembly is then coupled to head section38 by any suitable fastening means including screws, bolts, snaps,clasps, latches, or other suitable fastening means. As such, thesub-assembly may be configured for a variety of mattress configurationsand assembled into the remainder of patient support 10.

Foot Section

Referring further to FIG. 16, leg or foot section 42 is transverselycontoured similar to head section 38 and seat section 40. However, legsection 42 further includes a first leg section member 290 and a secondleg section member 292 which are movable relative to each other andthereby allow leg section 42 to be positioned in a retracted position,shown best in FIG. 18, and in an extended position shown best in FIG.20. In alternative embodiments, one or more of the head section 38, seatsection 40 and leg section 42 are comprised of multiple section membersthat are movable relative to each other to allow the respective sectionto lengthen or retract.

Referring to FIGS. 16 and 21, first leg section member 290 includes agenerally flat floor or wall 294 and angled side walls 291 a, 291 b.Second leg section member 292 includes a generally flat floor or wall298 and angled side walls 300 a, 300 b. Floor 298 and side walls 300 a,300 b of second leg section member 292 are configured to overlay floor294 and side walls 291 a, 291 b of first leg section member 290. Assuch, second leg section member 292 is configured to slide over firstleg section member 290 as leg section 42 is translated between anextended position (FIG. 20) and a retracted position (FIG. 18), orbetween a retracted position (FIG. 18) and an extended position (FIG.20). Alternatively, the first leg section member 290 is configured toslide over the second leg section member 292 as the leg section 42 istranslated between an extended position and a retracted position, orbetween a retracted position and an extended position.

Referring further to FIGS. 18 and 20, second leg section member 292 istranslated relative to first leg section member 290 by actuator 48 f. Afirst end 302 of actuator 48 f is coupled to first leg section member290 and a second end 304 of actuator 48 f is coupled to second legsection member 292. In the illustrated embodiment, first end 302 ofactuator 48 f is coupled to a bracket 303 of first leg section member290. Similarly, second end 304 of actuator 48 f is coupled to a bracket305 of second leg section member 292. To extend second leg sectionmember 292 relative to first leg section member 290, cylinder rod 172 fof actuator 48 f is extended. To retract second leg section member 292relative to first leg section member 290, cylinder rod 172 f of actuator48 f is retracted. In the preferred embodiment, actuator 48 f is anelectric actuator, such as a Linak actuator, and is controlled bycontrol system 44 as described herein. In alternative embodiments theactuator 48 f is a mechanical actuator, a pneumatic actuator, ahydraulic actuator, a link system or other suitable means to move thesecond leg section member 292 relative to the first leg section member290.

First leg section member 290 and second leg section member 292 aremaintained in longitudinal alignment at least in part by guide members306 a, 306 b. Illustratively, guide member 306 a, 306 b are telescopingtubes that extend and retract in a linear fashion as the first andsecond leg section members 290 and 292 move relative to each other. Asshown in FIG. 20, a first end 308 of guide members 306 are coupled tofirst leg section member 290 and a second end 310 of guide members 306are coupled to second leg section member 292. As such as actuator 48 fextends or retracts, guide members 306 are configured to extend orretract opposite sides of second leg section member 292 at the samerate, thereby preventing the second leg section 292 and the first legsection 290 from binding. In alternative embodiments, the guide membersmay comprise slide blocks and guide channels, interlocking members,rollers and associated races, or other suitable guiding means.

Referring to FIGS. 16 and 21, second leg section member 292 is furtherguided relative to first leg section member 290 by operably coupledinterlocking portions 312 a and 314 a of angled walls 291 and 300 a,respectively, and by operably coupled interlocking portions 312 b and314 b of angled walls 293 and 300 b, respectively.

Referring further to FIGS. 16 and 21, floor 294 of first leg sectionmember 290 and floor 298 of second leg section member 292 are separatedby a separator 316. Separator 316 is made of a material, such asplastic, that assists in the movement of second leg section member 292relative to first leg section member 290. In the illustrated embodiment,separator 316 includes a plurality of flexible finger members 318 whichare coupled to second leg section member 292 and contact first legsection member 290. Fingers 318 are connected to second leg sectionmember 292 to maintain the position of fingers 318 at the interfacebetween first leg section member 290 and second leg section member 292.In alternative embodiments, separator 316 may comprise a strip attachedto the end of the second leg section member 292, a series of rollers, orother means to facilitate the sliding of the second leg section member292 relative to the first leg section member 290.

In alternative embodiments other suitable extendable foot sections 42may be used. Illustrative suitable foot sections include the patientsupports and corresponding foot sections described in U.S. Pat. No.6,212,714 issued Apr. 10, 2001 to Allen et al., the disclosure of whichis expressly incorporated by reference herein, and U.S. Pat. No.6,163,903 issued Dec. 26, 2000 to Weismiller et al., the disclosure ofwhich is expressly incorporated by reference herein.

As previously mentioned, leg section 42 of deck 26 is adjustable inlength so that it can be moved from a retracted position to an extendedposition. Preferably, the length of leg section 42 is adjusted dependingupon the height of the patient positioned on mattress 14 so that thepatient's foot is positioned adjacent to footboard 18, shown in FIG. 1.For example, leg section 42 is extended to position the heels of a tallpatient adjacent to footboard 18. Leg section 42 is retracted toposition the heels of a shorter patient adjacent to footboard 18.

Also illustratively, mattress 14 is configured to be extended andretracted with leg section 42 as discussed in more detail herein. Assuch, the heel of the patient may be maintained over a given section ofmattress 14, such as heel pressure relief member 2154 (FIGS. 93-95)which is configured to provide heel-pressure relief.

According one embodiment of the present disclosure, the length of legsection 42 corresponds to the position of head section 38. For example,if head section 38 is raised to the titled position as shown in FIG. 21,leg section 42 of deck 26 is controlled by control system 44 toautomatically extend by a given distance. If head section 38 is lowered,leg section 42 is controlled by control system 44 to automaticallyretract to its pre-extended position. More particularly, control system44 coordinates movement of head section 38 and leg section 42 bysimultaneously controlling actuators 48 c and 48 f. By corresponding theextension and retraction of leg section 42 with the movement of headsection 38, the patient's foot is maintained above heel pressure reliefmember 2154 of mattress 14. Furthermore, if footboard 18 is used as afoot prop, the patient's foot is maintained at a steady distancerelative to footboard 18 during raising and lowering of head section 38.

Preferably, the degree of automatic extension of leg section 42 is afunction of the angle of head section 38. The further up head section 38is raised from a generally linear relationship with seat section 40, themore leg section 42 is extended so that heel pressure relief member 2154is continuously positioned under the patient's heel throughout the rangeof motion of head section 38.

Mattress Deck Articulation

As stated previously, patient support 10 is positionable in a pluralityof positions. Referring to FIGS. 1 and 3 and 22, head section 38, seatsection 40 and leg section 42 are in a linear relationship relative toeach other. In one illustrative embodiment, head section 38, seatsection 40 and leg section 42 are placed in the linear relationship bycontrol system 44 in response to a single button being depressed on oneof controllers 50, 52, 54.

Referring to FIG. 4, head section 38 is rotated about pivot 232 suchthat second end 235 is raised relative to first end 231. Second end 235is raised by control system 44 controlling actuator 48 c to furtherextend cylinder 172 of actuator 48 c. In one illustrative embodiment,head section 38 is raised by control system 44 in response a firstbutton being depressed on one of controllers 50, 52, 54 and lowered bycontrol system 44 in response to a second button being depressed on samecontroller 50, 52, 54.

Also, shown in FIG. 4, seat section 40 is rotated about pivot 237 suchthat second end 239 is raised relative to first end. Second end 239 israised by control system 44 controlling actuator 48 d to further extendcylinder 172 d of actuator 48 d. Leg section 42, in FIG. 4, is raiseddue to the rotation of seat section 40 and the coupling of leg section42 to seat section 40, but leg section 42 remains in a generallyhorizontal position due to the rotation of actuator 48 e. In oneillustrative embodiment, seat section 40 is raised by control system 44in response to a first button being depressed on same and lowered bycontrol system 44 in response to a second button being depressed on thesame controller 50, 52, 54.

Referring to FIG. 5, head section 38 and seat section 40 are ingenerally the same position as in FIG. 4. However, second end 250 of legsection 42 has been lowered such that second end 250 is lower relativeto first end 244. Second end 250 is lowered relative to first end 244 bycontrol system 44 controlling actuator 48 e to further retract cylinder172 e of actuator 48 e. In one illustrative embodiment, head section 38,seat section 40 and leg section 42 are placed in the configuration shownin FIG. 5 by control system 44 in response to a chair button on one ofcontrollers 50, 52, 54 being depressed. In an alternate embodiment, theleg section 42 is raised by control system 44 in response to a legsection up button being depressed on one of the controllers 50, 52, 54,and lowered by control system 44 in response to a leg section downbutton being depressed on the same controller 50, 52, 54.

Referring further to FIGS. 4, 5, 18 and 20, the weight of actuator 48 eand leg section 42 maintains a first end 320 of actuator 48 e adjacent afirst end 322 of slot 324 in bracket 246 as cylinder 172 e of actuator48 e is retracted, as opposed to first end 320 of actuator 48 etraveling towards a second end 326 of slot 324. The configuration ofdeck in FIG. 5 is an illustrative first chair-like position.

Further, leg section actuator 48 e is lengthened by control system 44when seat section 40 is lowered from the elevated position shown in FIG.5. Leg section actuator 48 e is lengthened to prevent any interferencebetween leg section 42 and seat section 40.

FIG. 6 illustrates leg section 42 not being movable between the positionof leg section 42 in FIG. 4 and the position of leg section in FIG. 5,due to an obstruction 330 impeding the movement of leg section 42.Example obstructions include a cart, a wheelchair, a table, a trashcanor any other item. As shown in FIG. 6, when leg section 42 encountersobstruction 330 first end 320 of actuator 48 e travels along elongatedslot 324 in the direction of arrow 325 toward second end 326 of slot324. As such, slot 324 serves as a safety device to avoid crushingobstruction 330 and to avoid destruction of actuator 48 e and damage topatient support 10.

The length of slot 324 is selected to allow actuator 48 e to move from afully extended position to a fully retracted position while first end320 of actuator 48 e travels in slot 324. As such, actuator 48 e willencounter the end of its range of motion or travel (fully retracted)before or coincident with first end 320 of actuator 48 e reaching secondend 326 of slot 324. Therefore, leg section 42 will not crush orotherwise damage obstruction 330 due to the continued pressure appliedby actuator 48 e, actuator 48 e will not be damaged due to a larger thanexpected load being placed on actuator 48 e, and patient support 10 willnot be damaged.

Alternative methods may be used to keep the leg section 42 from damagingthe obstruction and to keep from damaging the actuator 48 e. A firstexample is to monitor the load placed on the actuator 48 e with thecontrol system 44 and to disengage or reverse the motion of the actuator48 e in response to a larger than expected load for retracting theactuator 48 e. A second example is to place a pressure sensor along thebottom of the leg section 42 and to disengage the actuator 48 e when ahigher than expected pressure is detected. An illustrative sensor may bethe obstacle detection system of the present invention disclosed herein.Other known safety systems may also be used.

In alternative embodiments, the elongated slot 324 is located on thebracket 248 attached to the weigh frame 36 and the actuator 48 e ispivotably coupled to the leg section 42 and slidably and pivotablycoupled to the weigh frame 36. In a further alternative embodiment, theelongated slot 324 is located on the joint between the leg section 42and the seat section 40 such that the leg section 42 and the seatsection 40 are pivotably and slidably coupled, the leg section 42 andthe actuator 48 e are pivotably coupled and the actuator 48 e and theweigh frame 36 are pivotably coupled. In still further alternativeembodiments, the elongated slot 324 feature is incorporated into theconfiguration for the head section 38, is incorporated into theconfiguration for the seat section 40, or is incorporated into thelifting arms 34 configuration.

Referring to FIG. 10, a second chair-like configuration of patientsupport 10 is shown. Head section 38, seat section 40 and leg section 42of deck 26 are generally oriented relative to intermediate frame 32 asshown in FIG. 5. However, deck support 24 is positioned generally in aReverse Trendelenburg position, wherein foot end 104 of intermediateframe 32 is lower than head end 102 of intermediate frame 32. Decksupport 24 is placed in the second chair-like position by retractingactuator 48 b, shown in FIG. 2, and thus lowering foot links 108. In oneillustrative embodiment, patient support 10 is placed in theconfiguration shown in FIG. 10 by control system 44 in response to afirst button being depressed on one of controllers 50, 52, 54 and inresponse to a second button being depressed on one of controllers 50,52, 54. In an alternative embodiment, the patient support is placed inthe configuration shown in FIG. 10 in response to a button beingdepressed on the controllers. In a further alternate embodiment, thepatient support 10 is placed in the configuration of FIG. 5 in responseto a first chair button on one of controllers 50, 52, 54 being depressedand is placed in the configuration of FIG. 10 in response to a secondchair button on the same controller 50, 52, 54 being depressed.

A further safety device 340 is shown in FIG. 17 and is coupled to legsection 42. Safety device 340 includes bracket 305 rigidly coupled toleg section 42 and a roller 344 rotatably coupled to bracket 305. Safetydevice 340 similar to slot 324 protects patient support 10 from damageand also protects an obstruction, such as obstruction 330 or the floor29 (FIG. 6), from damage. Alternatively, the roller 344 of the safetydevice 340 is directly coupled to or integrated with the leg section 42,thereby eliminating the bracket 305.

In FIG. 11, patient support 10 is transitioned to the second-chair likeconfiguration, however either due to the fact that leg section 42 isextended, discussed in more detail herein, or that deck support 24 issomewhat lowered, second end 250 of leg section 42 contacts the floorand could potentially be damaged prior to patient support 10 fullytransitioning to the second chair like position. As shown in FIG. 11,safety device 340 is configured to translate second end 250 of legsection 42 in a direction 341 while leg section 42 rotates in adirection 343 to avoid damage to leg section 42.

As second end 250 of leg section 42 is translated in direction 341 andleg section 42 is rotated in direction 343 relative to seat section,first end 320 of actuator 48 e is traveling within slot 324. Asdiscussed earlier in connection with FIG. 6, slot 324 allows theactuator 48 e to continue to retract without further lowering legsection 42. However, in the current case, wherein patient support 10 istransitioning from the first chair-like configuration of FIG. 5 to thesecond chair-like configuration of FIG. 10, actuator 48 e is notretracting. In the current case of FIGS. 10 and 11, first end 320 ofactuator 48 e, a fixed link (since not retracting or extending), travelswithin slot 324 and thus leg section 42 rotates to avoid crushing theobstruction or causing damage to the patient support 10. As such, safetydevice 340 functions in concert with slot 324. It should be appreciatedthat roller 344 reduces the friction between the floor 29 and legsection 42, thereby allowing leg section 42 to more easily rotate andtranslate.

A further instance wherein safety device 340 protects both leg section42 and an obstruction from damage is when deck 26 is in a linearconfiguration with leg section 42 in an extended position and thepatient support 10 is moved to a Reverse Trendelenburg position from alow position. As shown in FIG. 12, patient support 10 is transitioningfrom a low position, wherein both actuators 48 a and 48 b, shown in FIG.2, are generally retracted, to a Reverse Trendelenburg position, whereinactuator 48 b remains generally retracted and actuator 48 a is generallyextended to raise head end 102 of intermediate frame 32 relative to footend 104. In such a configuration, the second end 250 of leg section 42could either contact the floor 29 or an obstruction 348, such as a foot.In either case, safety device 340 and safety device 324 cooperate torotate leg section 42 relative to seat section 40 and thereby reduce thelikelihood of damage to both leg section 42 and the obstruction 348.

CPR Configuration

Often it is required to configure patient support 10 in a CPRconfiguration which is tailored to assist a caregiver in providing CPRto the patient supported on patient support 10. In one illustrativeexample, a CPR configuration is defined by placing the head, seat andleg sections 38, 40, 42 in a generally linear relationship and toinflate an upper bladder assembly 2122 to an elevated or a maximumpressure in the manner further described herein. In a furtherillustrative CPR configuration, the head, seat and leg sections 38, 40,42 are placed in a generally linear relationship, the upper bladderassembly 2122 is inflated to an elevated or a maximum pressure anddecking support 24 is oriented such that head end 102 is lower relativeto foot end 104, generally a Trendelenburg position as shown in FIG. 9.

Patient support 10 may be placed in the preferred CPR configuration byproviding an indication to control system 44 which in turn controlsactuators 48 c, 48 d, 48 e to place head, seat, and leg sections 38, 40,42 in a generally linear relationship, controls pump 64 to inflate upperbladder assembly 2122 to the desired pressure, and controls actuators 48a and 48 b of deck support 24 to lower head end 102 relative to foot end104. The details of control system 44 and how control system 44 controlsactuators 48 a-f and pump 64 are further described herein.

Illustratively, patient support 10 is placed in the preferred CPRconfiguration by manually lowering head section 38 to a lowered positionand providing an indication to control system 44 which, in turn,controls actuators 48 d and 48 e to place head, seat and leg sections38, 40, 42 in a linear relationship, controls pump 64 to inflate upperbladder assembly 2122 to the desired pressure, and controls actuators 48a and 48 b of deck support 24 to lower head end 102 relative to foot end104. Referring to FIG. 18, both the manual lowering of head section 38and the providing of an indication to control system 44 are initiated bythe actuation of a first or user input 350 from a first statecorresponding to an off or inactive condition to a second statecorresponding to an on or active condition and are continued as long asfirst input 350 remains in the on or active condition.

Referring to FIGS. 13, 16, 18, 23 and 24, first input 350 includes ahandle 352 positioned adjacent a longitudinal side of head section 38.As shown in FIG. 24, a pair of first inputs 350 are provided, each firstinput member 350 being supported adjacent opposing right or leftlongitudinal sides of the head section 38. In the following description,the first inputs 350 and related components adjacent the left and rightsides will be specifically identified by the respective reference numberfollowed by reference letter “a” or “b”. It should be appreciated thatboth first inputs 350 a and 350 b have identical components and aremirror images of each other. Further, each first input 350 a and 350 bis configured to function independently of the other first input 350 aand 350 b. Each handle 352 is coupled to a handle bracket 354 which isrotatably coupled to a bracket 356 which is rigidly coupled to headsection 38. Handle bracket 354 is rotatably coupled to bracket 356 by afirst fastener 358. The degree of rotation of handle bracket 354relative to bracket 356 is limited by a stop, illustratively fastener360 (FIG. 23), which is received in an elongated slot 362 in handlebracket 354.

In one illustrative embodiment, handle 352 includes an indicia 353,shown in FIG. 16, that indicates that the handle corresponds to a CPRcondition. Illustrative indicia includes wording such as “CPR” or othertext, color-coding, embossed characters or combinations thereof. Inalternative embodiments, the indicia is a part of a pedal, a button, aswitch, a lever arm, or other suitable actuatable members Referringfurther to FIG. 23, each handle bracket 354 includes a flange 364 thatis configured to couple a first end 366 of a cable 368. Bracket 356includes a flange 370 configured to couple a first end 372 of a cablehousing 374. Cable 368 is free to translate or move within cable housing374. As such, as handle bracket 354 is rotated in direction 376 relativeto bracket 356, cable 368 is extended from cable housing 374 generallyin direction 378. As explained later, cable 368 biases in direction 380,in the absence of an external force applied to handle 352, therebycausing handle bracket 354 and handle 352 to rotate in direction 381,opposite direction 376.

Referring to FIGS. 24-28, a second end 382 of each cable 368 and asecond end 384 of each cable housing 374 are coupled to an actuatorassembly 386 which, in turn, is coupled to actuator 48 c. Actuatorassembly 386 includes a housing 388 coupled to cylinder rod 172 ofactuator 48 c by retainers 390, shown in FIGS. 24 and 25. Flange 392extends from a top portion 394 of housing 388 and is configured tocouple to second end 384 of each cable housing 374. A slide bracket 396is slidably coupled to top portion 394 of housing 388. Slide bracket 396receives second end 382 of each cable 368 in one of the plurality ofslots 400 defined by a plurality of upwardly extending flanges 402 ofslide bracket 396. A further flange 404 of slide bracket 396 is coupledto a release pin 406 of actuator 48 c. As known in the art, release pin406 of actuator 48 c is configured to allow cylinder rod 172 c ofactuator 48 c to freely move relative to cylinder body 170 c, such thatrod 172 c can be freely extended from or retracted within cylinder body170 c.

Slide bracket 396 is coupled to each handle bracket 354 through cables368. As such, the rotation of either handle 352 a, 352 b by a caregiverrotates respective handle bracket 354 a, 354 b which, in turn,translates first end 366 a, 366 b of cable 368 a, 368 b away from firstend 372 a, 372 b of cable housing 374 a, 374 b, which translates secondend 382 a, 382 b of cable 368 a, 368 b toward second end 384 a, 384 b ofcable housing 374 a, 374 b in a direction 408 (FIG. 26). The translationof either cable 368 a, 368 b in direction 408 translates both slidebracket 396 and release pin 406 in direction 408. As such, while thecaregiver keeps either handle 352 a, 352 b in its rotated position,cylinder rod 172 c of actuator 48 c is freely moveable relative tocylinder body 170 c of actuator 48 c and head section 38 may be manuallylowered or raised.

As known in the art, release pin 406 is biased in direction 410 counterto direction 408. As release pin 406 moves in direction 410, cylinderrod 172 c of actuator 48 c is no longer freely movable relative tocylinder body 170 of actuator 48 c. Therefore, when the caregiverreleases both handles 352 a, 352 b release pin 406 due to its biastranslates slide bracket 396 in direction 410 which in turn throughrespective cables 368 a, 368 b rotates handle bracket 354 a, 354 b andhandle 352 a, 352 b in direction 381 (FIG. 23). As such, actuator 48 cis once again actuatable by control system 44 instead of manually.

Referring to FIG. 25, as the caregiver manually lowers head section 38,a damper 430 is provided to reduce the rate at which head section 38 islowered thereby ensuring that head section 38 does not abruptly move tothe lowered position. Illustratively, damper 430 is a gas spring 432which is pivotably coupled to weigh frame 36 and slidably and pivotablycoupled to head section 38. A first end 434 of gas spring 432 isreceived in an elongated slot 436 of a bracket 438 which is rigidlycoupled to head section 38. As head section 38 is lowered from theelevated position to an intermediate position, first end 434 of damper430 travels from a first end 440 of slot 436, generally corresponding tothe elevated position, towards a second end 442 of slot 436, generallycorresponding to the intermediate position. In an illustrativeembodiment, the intermediate position corresponds to a positionapproximately two-thirds of the travel distance from the elevatedposition to the lowered position.

Gas spring 432 has an uncompressed state generally corresponding to headsection 38 being positioned between the intermediate position and theelevated position and a compressed state generally corresponding to headsection 38 being positioned between the intermediate position and thelowered position. As head section 38 moves from the intermediateposition to the lowered position, first end 434 of gas spring 432 staysproximate to second end 442 of slot 436 and a rod 444 of gas spring 432is forced to slidably move into a housing 446 of gas spring 432 againstthe biasing force exerted by gas spring 432. In general, gas spring 432prefers to be in the uncompressed state and resists movement to thecompressed state. As such, gas spring 432 resists the movement of headsection 38 from the intermediate position to the lowered position andthereby slows the rate of travel of head section 38 to the loweredposition.

Gas spring 432 is of conventional design. In alternative embodiments,other types of dampers may be used. Example dampers include compressiblefoam, air bladders, compressible springs, and other suitable dampingmeans.

Referring to FIG. 26, housing 388 further includes a second input orcontrol 448 that is connected to control system 44. Illustratively,second input/CPR release 448 is a switch which is engaged by slidebracket 396. When switch 448 is closed, control system 44 receives anindication that switch 4148 s been closed. Control system 44 proceeds toplace the other portions of patient support 10 in the preferred CPRconfiguration. First, control system 44, if needed, actuates actuators48 d and 48 e to place seat section 40 and leg section 42 in a linearrelationship with head section 38 corresponding to head section 38 beingin a lowered position. Second, control system 44, if needed, inflatesupper bladder assembly 2122 to the desired pressure. Third, controlsystem 44, if needed, actuates actuators 48 a and 48 b to lower head end102 of decking support 24 relative to foot end 104 of decking support24. If switch 448 remains closed, control system 44 preferably lowershead end 102 about 12° to about 15° relative to foot end 104.

If switch 448 is opened as a result of the caregiver releasing handle352 before control system 44 completes the aforementioned tasks, controlsystem 44 aborts the uncompleted tasks. For example, if the caregivercould release handle 352 when head end 102 is approximately 5° lowerthan foot end 104. It is understood that switch 448 may be located in avariety of locations and activated in a variety of ways. For instance,switch 448 may be placed on handle 352 or handle bracket 354. Inalternate embodiments, the handle 352 is replaced by a foot pedal, abutton, a switch, a lever arm or other suitable actuatable members.

Referring to FIG. 28, a second embodiment slide bracket 420 is shown.Slide bracket 420 is made from a plastic material and generallyfunctions similar to slide bracket 396. Slide bracket 420 is slidablycoupled to housing 388, is coupled to release pin 406, and is configuredto engage switch 448. Slide bracket 420 is further coupled to secondends 3822, 382 b of cable 368 a, 368 b.

Referring to FIG. 30, second end 382 of each cable 368 includes aretainer 421 which is received within a recess 422 on slide bracket 420.Illustratively, the retainer 421 may comprise a spherical member or adisk crimped on the second end 382 of cable 368. In order to enterrecess 422, retainer 421 on second end 382 must pass by detent 424 whichis configured to retain second end 382 in recess 422.

Caster Braking System

Referring to FIGS. 29-33, patient support 10 further includes a casterbraking system 450. The caster braking system 450 interconnects eachcaster device 30 a, 30 b, 30 c, 30 d to provide simultaneous braking ofcasters devices 30 a, 30 b, 30 c, 30 d. Each caster device 30 a, 30 b,30 c, 30 d is associated with a foot brake pedal 452 a, 452 b, 452 c,452 d. To simultaneously brake all caster devices 30 a, 30 b, 30 c, 30d, the caregiver steps on one of foot brake pedals 452 and casterbraking system 450 locks all four caster devices 30 a, 30 b, 30 c, 30 dagainst rolling. In alternative embodiments the caster devices 30 arebrake/steer caster devices opposed to simply brake caster devices.

Each caster device 30 includes a braking mechanism (not shown) that iscoupled to a caster-brake link, illustratively a faceted shaft such ashexagonal shaft 453, such that rotation of hexagonal shaft 453 engagesthe braking mechanism. As shown in FIG. 32, each hexagonal shaft 453 isreceived within a sleeve 454 of caster device 30 wherein shaft 453 iscoupled to the braking mechanism. Additional description of a casterbraking system similar to the caster braking system 450 of the presentdisclosure including the illustrative braking mechanism is provided inU.S. patent application Ser. No. 09/263,039, filed Mar. 5, 1999, toMobley et al., entitled Caster and Braking System, and issued as U.S.Pat. No. 6,321,878 on Nov. 27, 2001, the disclosure of which isexpressly incorporated by reference herein. According to alternativeembodiments of the present disclosure other configurations of casterbraking and/or steering systems with or without simultaneous lockingfunctions are provided for use with the foot brake pedal 452 andcaster-brake link of the present disclosure.

As shown in FIGS. 29 and 31, a first end 455 of hexagonal shaft 453 iscoupled to foot pedal 452. A second end 456 of hexagonal shaft 453 iscoupled to a rod 457. Rods 457 a, 457 b interconnect transversely spacedcaster pairs 30 a, 30 b and 30 c, 30 d, respectively. Rod 457 a iscoupled to hexagonal shafts 453 a and 453 b and rod 457 is coupled tohexagonal shafts 453 c and 453 d. As such, the braking of either casterdevice 30 a or caster device 30 b results in the braking of the othercaster device of caster device 30 a and caster device 30 b. Similarly,the braking of either caster device 30 c or caster device 30 d resultsin the braking of the other caster device 30 c or caster device 30 d.

Further, transversely spaced caster device pairs 30 a, 30 b and 30 c, 30d are interconnected by a longitudinally extending brake links 458 a,458 b, respectively. Brake links 458 a, 458 b are configured to interactwith the caster device pairs 30 a, 30 b, 30 c, 30 d such that thebraking of any one caster device 30 a, 30 b, 30 c, 30 d simultaneouslybrakes the remaining caster devices 30 a, 30 b, 30 c, 30 d.

As shown in FIGS. 29 and 32, a first end 460 of brake link 458 a ispivotably coupled to a bracket 462 a by a fastener 464. Illustrativelybracket 462 is a U-shaped bracket having a first leg 466 and a secondleg 468. The lower portions of legs 466, 468 are configured to pivotablycouple to brake link 458. Bracket 462 further includes a generallyhexagonal opening for coupling bracket 462 to hexagonal shaft 453.

In operation, a caregiver depresses one of the foot pedals 452, such asfoot pedal 452 a, to simultaneously brake all four caster devices 30 a,30 b, 30 c, 30 d. Illustratively, foot pedals 452 are shown on a firstside of each caster device 30. Alternatively, the foot pedals 452 may belocated on the other side of the caster devices 30 or each caster device30 could have more than a single foot pedal 452 associated with thecaster device 30. The depressed foot pedal 452 a causes the rotation ofhexagonal shaft 453 a in direction 470 as illustrated in FIG. 29.

The rotating of hexagonal shaft 453 a in turn engages the brakingmechanism (not shown) of caster device 30 a, rotates rod 457 a indirection 470 and rotates bracket 462 a in direction 470. The rotationof rod 457 a further rotates hexagonal shaft 453 a in direction 470thereby engaging the brake mechanism of caster device 30 b. The rotationof bracket 462 a translates brake link 458 a in a direction 472. Thetranslation of brake link 458 a in direction 472 results in the rotationof bracket 462 c in direction 470 which, in turn, rotates hexagonalshaft 453 c in direction 470, thereby engaging the brake mechanism ofcaster device 30 c. The braking mechanism of caster device 30 d isengaged by the rotation of hexagonal shaft 453 d either through thetranslation of brake link 458 b similar to the translation of brake link458 a and/or through the rotation of rod 457 b similar to the rotationof rod 457 a. In alternative embodiments, the caster braking system 450includes only two transverse rods 457 and a single brake link 458 or twobrake links 458 and a single transverse rod 457.

In order to unlock the caster braking system 450 of the presentinvention, one of the four pedals 452, such as pedal 452 a is rotated ina direction 473 counter to the direction 470, thereby disengaging thebraking mechanism of caster device 30 a. The braking devices of casters30 b, 30 c, 30 d are disengaged in a manner similar to how they areengaged through rods 457 a, 457 b and brake links 458 a, 458 b.

As stated previously, it is advantageous to lower intermediate frame 32as low as possible to the floor to aid egress from and ingress topatient support 10 and to prevent injury in case of accidental fall frompatient support 10. The configuration of caster braking system 450 has alow profile which provides additional clearance for deck 26, siderails20, 22 and other patient support components as deck support 24 islowered. As such, intermediate frame 32 can be further lowered. As shownin FIG. 31, brake links 458 a, 458 b of caster brake system 450 extendsthrough longitudinal frame member 192 and brake link 458 b extendsthrough longitudinal frame member 194. As shown in FIG. 33, brake links458 are positioned lower than hexagonal rods 453 such that a top surface474, 476 of longitudinal frame members 192, 194 can be lower to thefloor 29. Therefore, greater clearance is provided and intermediateframe 32 can be further lowered relative to base frame 28.

Control System

Referring now to FIG. 35, control system 44 includes various controls,interfaces, sensors, and actuators that communicate via a plurality ofcontrol modules (described below) connected together by a network 510. Acontrol system having certain characteristics in common with controlsystem 44 is described in U.S. Pat. No. 5,771,511 (hereinafter “the '511patent”), which is hereby expressly incorporated herein by reference.Unlike the peer-to-peer network described in the '511 patent, network510 is a controller area network (CAN) having a serial bus connectingthe modules, each of which includes a controller, a transceiver andassociated electronics. In one embodiment, the bus includes a twistedpair of wire conductors. In general, each module is capable oftransmitting data on the bus (when the bus is idle), and multiplemodules can simultaneously access the bus. Information transmissions (ormessages) are not addressed for receipt by a specific module. Instead,as will be further described below, each message is broadcast on the busto all modules, and includes an identifier that each module uses todetermine whether to process the message. If the message is relevant toa particular module, it is processed. Otherwise, it is ignored.

As shown in FIG. 35, seven modules are connected to network 510 forcontrolling the operation of patient support 10. The modules include alogic module 512, a power supply module 514, a scale/ppm module 516, adynamic surface module 518, a left caregiver module 520, a rightcaregiver module 522, and a sidecomm module 524. With reference to FIG.35B, logic module 512 is electrically coupled to detachable siderailcontroller 50 (or patient pendant(s)), CPR release switch 448, DC motors604 of linear actuators 48, and a plurality of sensors including siderail position sensors 60, a head up sensor 534, a head down sensor 536,a foot sensor 538, a foot safety detect sensor 540, a knee contoursensor 542, a bed-not-down sensor 544, and motor sensors 546.

As illustrated in FIG. 35D, power supply module 514 is electricallycoupled to obstacle detection device 58, a night light 548, foot pedalcontrols 56, battery 46, a battery charger 552, pneumatic pump 64, andpower conditioning circuitry 556. Power supply module 514 furtherincludes a connector (not shown) for receiving a test device 558 forperforming various diagnostic and test functions. Power conditioningcircuitry 556 is connected to a conventional AC plug 45. With referenceto FIG. 35A, scale/ppm module 516 is electrically coupled to the loadcells 220, 222, 224, 226 connected to weigh frame 36, and to a bed exitsensor 562.

With reference to FIG. 35A, dynamic surface module 518 is electricallycoupled to a plurality of solenoids 564 for controlling characteristicsof mattress 14, and a plurality of pressure transducers 566 associatedwith mattress 14 for sensing air pressures of various components ofmattress 14. Left caregiver control module 520 is electrically coupledto first pair of permanent siderail controllers 52 mounted to left headend siderail 20. Right caregiver control module 522 is similarlyelectrically coupled to first pair of permanent siderail controllers 54mounted to right head end siderail 20. The configuration and operationof first and second pair of permanent siderail controllers 52, 54 arefurther described elsewhere herein. Finally, with reference to FIG. 35C,sidecomm module 524 is electrically coupled to room lighting controls568, a nurse call control 570, a remote network interface 572,entertainment equipment 574 (e.g., radio and television), and abrake-not-set sensor 576.

It should be understood that the configuration of network 510 permitsaddition of new modules and subtraction of existing modules withoutrequiring manual reconfiguration of the existing modules. When a newmodule is added, network 510 recognizes the module and facilitatescommunications between the added module and the existing modulesautomatically. Additionally, it should be noted that network 510 isimplemented to operate as a masterless system, wherein each module 512,514, 516, 518, 520, 522, 524 operates substantially autonomously. Onefeature of network 510 is the periodic transmission of each module 512,514, 516, 518, 520, 522, 524 of a “heartbeat” message or status messageto the bus for receipt by each of the remaining modules. In this manner,control system 44 periodically verifies the functionality of each module512, 514, 516, 518, 520, 522, 524 in system 44, and is able to identifya non-operational module by the absence of the module's “heartbeat”message. As further described herein, communications by and amongmodules 512, 514, 516, 518, 520, 522, 524 are initiated by theindividual modules on an event-driven basis.

Power for control system 44 is supplied through power supply module 514.More specifically, AC plug 45 of a power cord (not shown) secured toframe 12 is inserted into a conventional wall outlet supplying 100 VAC,120 VAC, or 230 VAC power. Power conditioning circuitry 556 converts theAC input power to DC levels for use by the various electronic componentsof control system 44. Power supply module 514 further facilitateslimited functionality of patient support 10 via battery 46 when AC plug45 is not connected to a wall outlet. Battery 46 is automaticallycharged by battery charger 552, which provides a status signal to powersupply module 514 to indicate the condition of the charge of battery 46.In one embodiment, battery charger 552 permits use of battery 46 as aback-up power source that allows logic module 512 to perform (for 24hours after AC power has been disconnected) a single operation ofhigh-low up/down, head up/down, tilt/reverse tilt, foot retract/extend,Trendelenburg, and chair out. When AC power is applied to patientsupport 10, a light emitting diode (LED) 737 (FIG. 31) indicates thestatus of battery 46. For example, the LED remains lit when battery 46has sufficient power, blinks when battery 46 power is low, or is offwhen battery 46 has lost all power or is disconnected. As indicated,power supply module 514 controls the operation of pneumatic pump 64 (ora blower or other type of inflating means), which supplies air tomattress 14 (as described in greater detail below).

Power supply module 514 also receives the signal provided by obstacledetection device 58 as described herein. Power supply module outputs amessage on network 510 when obstacle detection device 58 outputs asignal indicating the presence of an obstacle so that appropriate actioncan be taken to prevent injury or damage.

Power supply module 514 also controls night light 548. Specifically,night light 548, which illustratively is mounted to patient support 10at a location to illuminate the ingress/egress area of patient support10, is always active or on when AC power is provided to power supplymodule 514. Night light 548 may be disabled or shut off during batterypowered operation. As further described herein, the illumination element(not shown) of night light 548 is enclosed by a housing, which alsoincludes circuitry (not shown) to prevent flicker.

As further described herein, each foot pedal 1724, 1726, 1728, 1730 offoot pedal controls 56 provides a signal when depressed. Power supplymodule 514 uses these signals to generate messages for transmission onnetwork 510 indicating the status of pedals 1724, 1726, 1728, 1730.Logic module 512 processes such messages to determine whether foot pedalcontrols 56 are enabled, and to control the operation of DC motors 604of linear actuators 48, as further described herein. Of course,operation of DC motors 604 is conditioned upon the actual positions ofthe various components of patient support 10, and upon the status ofvarious lockout signals generated by a caregiver using siderailcontrollers 52, 54.

Finally, power supply module 514 functions as an input location via aconnector (not shown) for test device 558. Test device 558 is configuredto operate as an additional module on network 510 for performingdiagnostic operations on the various functions of patient support 10 asis further described herein.

Scale/ppm module 516 converts the signals from load cells 220, 222, 224,226, described above, into actual weight measured on weigh frame 32.This information is outputted for display on a scale display (not shown)and possible transmission to a hospital information network via sidecommmodule 524 and remote network interface 572. Scale/ppm module 516further receives input from bed exit sensor 562, which determines, basedon the weight measured on weigh frame 32, whether a patient has exitedpatient support 10.

Dynamic surface module 518 controls the dynamic air surface or mattress14. It processes messages initiated by either of siderail controllers52, 54 to operate solenoids 564 (part of valve assemblies 2406), whichin turn adjust the level of inflation of mattress 14 during, forexample, a turn assist procedure as further described herein.Additionally, dynamic surface module 518 receives feedback from pressuretransducers 566 in the form of electrical signals that indicate pressuremeasurements of the various bladders of mattress 14. Dynamic surfacemodule 518 operates solenoids 564 in response to the feedback signalsfrom pressure transducers 566 to achieve the desired adjustments tomattress 14.

Sidecomm module 524 functions essentially as an environmental andcommunications interface. The nurse call, lighting, and entertainmentfunctions are controlled by sidecomm module 524 based on inputs fromsiderail controllers 50, 52, 54. Sidecomm module 524 outputs signals tocontrol these functions, and communicates with the facility'scommunication systems via remote network interface 572. Patient support10 includes a connector 575 (FIG. 30) that is configured to interfacewith the facility's communication system and entertainment system.Another connector (not shown) is provided to interface with the nursecall control 570 and lighting controls 568. As such, sidecomm module 524controls room lights, reading lights, television, radio, andcommunicates with the facility's nurse call network in response toactivation of a nurse call switch or button mounted to patient support10. Through remote network interface 572, sidecomm module 524 canprovide information to the facility's information network regarding theoperation of patient support 10. For example, hours of use may bereported for billing or maintenance purposes. Moreover, sidecomm module524 can function as an interactive data link between a remote locationand patient support 10. For example, the facility information networkmay request weight information on the patient occupying patient support10. Sidecomm module 524 can send a message on the bus identified as aweight request. The message may be processed by scale/ppm module 516,which provides a message containing the requested weight information.Sidecomm module 524 processes the message and provides the weightinformation to the facility's information network via remote networkinterface 572. Additionally, brake-not-set sensor 576 provides an inputto sidecomm module 524 to indicate that the brake preventing movement ofpatient support 10 is not in a set position.

Logic module 512 controls movement of patient support 10 and is theentry point for nearly all of the position sensors for the variouscomponents of patient support 10. As shown, logic module 512 controlsthe plurality of motors 604 of linear actuators 48 connected to themoveable components (e.g., the articulating deck sections 38, 40, 42,etc.) of patient support 10, as is described in detail herein. When a DCdrive motor 604 is activated, a motor sensor 546 associated with thedrive motor 604 provides a feedback signal to logic module from whichlogic module 512 can determine when to deactivate the drive motor 604.When logic module 512 processes a message requesting movement of aparticular component of patient support 10, logic module 512 first readsthe position of the component (via the appropriate sensor 546). Ifmovement of the component is necessary, then logic module 512 determineswhether a lockout signal has been generated from either of the first orsecond pair of permanent siderail controllers 52, 54. If no lockout isset, logic module 512 controls the appropriate DC drive motor 604, whilemonitoring the appropriate motor sensor 546, to move the component tothe desired position.

Controller Area Network

In one illustrative embodiment, CAN specification 2.0B as specified inISO 11898 is used for network 510. Network 510 involves three of theseven network layers defined in the ISO model: the physical layer, thedata link layer and the application layer. The physical layer includesthe actual cabling or wires connecting modules 512, 514, 516, 518, 520,522, 524. The physical layer further includes the hardware present oneach of modules 512, 514, 516, 518, 520, 522, 524 for enabling operationaccording to the CAN specifications. As indicated above, the hardwareincludes a transceiver for communicating with the bus and amicrocontroller with a built-in CAN controller. A suitable transceiveris a TJA1054 CAN transceiver manufactured by Philips Electronics. Asuitable microcontroller is a T89C51CC01 microcontroller manufactured byAmtel. The microcontroller is connected to a crystal oscillator, such asa 20 MHz crystal.

The data layer generates and receives the messages used forcommunications between modules 512, 514, 516, 518, 520, 522, 524 via theCAN protocol (described below).

The application layer complies with the CANopen specification as furtherdescribed below. CANopen is an open standard based on a model includingcommunication interface and protocol software, an object dictionary, andan application program interface. The communication interface andprotocol software provides a means by which a CANopen device cantransmit and receive messages over network 510. The object dictionary isa collection of all of the system variable information communicated overnetwork 510. Finally, the application program interface controls how theapplication software interacts with the various network parameters.

The communication interface and protocol software includes a variety ofservices and protocols. One protocol that handles real-time transfer ofdata between modules is the Process Data Objects (PDO) protocol. Two PDOservices are provided: receive (RPDO) and transmit (TPDO). RPDOs areused to obtain updated information for the object dictionary entries ofa module 512, 514, 516, 518, 520, 522, 524. TPDOs, on the other hand,are used to transmit updated information to object dictionary entries ofanother module 512, 514, 516, 518, 520, 522, 524. According to oneembodiment of the invention, eight PDOs can be used for each module 512,514, 516, 518, 520, 522, 524 (four configured as RPDOs and fourconfigured as TPDOs). Each PDO can transfer up to eight bytes ofinformation. While both PDO services share the same basic structure,TPDOs are essentially broadcast messages (any module 512, 514, 516, 518,520, 522, 524 could receive a TPDO), and RPDOs must be unique for eachmodule 512, 514, 516, 518, 520, 522, 524 that transmits. For example,power supply module 514 may send battery status information to all othermodules 512, 516, 518, 520, 522, 524 using a single TPDO. Each module512, 516, 518, 520, 522, 524 that needs to use the information must havea corresponding RPDO to receive the information from power supply module514. Moreover, each module 512, 514, 516, 518, 520, 522, 524 that needsinformation from any other module 512, 514, 516, 518, 520, 522, 524 musthave a separate RPDO for the other module 512, 514, 516, 518, 520, 522,524. In other words, RPDOs can only receive a message from a singlemodule.

PDOs are constructed from object dictionary entries in the mannerdepicted in FIG. 35. As shown, PDO 578 is capable of including eightbytes 580 of information. In this example, PDO 578 includes only fivebytes 580 of information. The eight bytes 580 of information can comefrom any of a variety of different object dictionary entries (such asobject dictionary entries 582 and 584) associated with differentmodules, and the entire data type for the object dictionary entry doesnot have to be used. Where the entire data type is not used, then thenumber of bits specified (starting with the LSB) are used as shown inFIG. 35.

PDOs of control system 44 are event driven. When an object dictionaryentry changes, for example, because a system variable changed, thecorresponding PDO is automatically transmitted, and the objectdictionary entry is automatically updated when a message is received. Asexplained herein, modules 512, 514, 516, 518, 520, 522, 524 determinewhich messages to process by analyzing an identifier included in themessage. The identifier includes three digits in the form of x8y where xis the TPDO of the transmitting module 512, 514, 516, 518, 520, 522, 524and y is the module ID of the transmitting module 512, 514, 516, 518,520, 522, 524. Thus, if a module 512, 514, 516, 518, 520, 522, 524 mapsone of its RPDOs with the CAN identifier 584, it correlates to TPDO2from module 4.

Another protocol is the Service Data Objects (SDO) protocol, which isadministered only by a master module. As indicated herein, controlsystem 44 includes a master only when test device 558 is coupled topower supply module 514. In that case, SDOs allow test device 558 accessto any object dictionary entry present in the other modules 512, 514,516, 518, 520, 522, 524.

The object dictionary defines data types, communication objects, andapplication objects used on network 510. The object dictionary isessentially a group of objects that are accessible via network 510 in apredefined, ordered fashion, using either SDOs or PDOs. All entries in aobject dictionary use a “wxyz” format where w is 2 if used by a PDO, 3if used by an SDO, x is the module identifier for the transmittingmodule 512, 514, 516, 518, 520, 522, 524, y is 0 if the entry includeserror information, 1 if it includes status information, and 8 if itincludes control information, and z is a unique value for multiple wxyentries. For example, an object dictionary entry of 2110 indicates thatthe information is communicated between modules 512, 514, 516, 518, 520,522, 524 during normal operation (i.e., using a PDO as opposed to an SDOused only during testing and diagnostics), that module number 1 is thetransmitter of the information (e.g., scale/ppm module 516), and that itincludes status information. The 0 indicates the unique value formultiple wxy entries.

Although in a typical CANopen implementation nodes only have objectdictionary entries to information generated or received by the node, incontrol system 44, all PDO object dictionary entries (2xyz) areimplemented in every module 512, 514, 516, 518, 520, 522, 524 tominimize the variance in software among modules 512, 514, 516, 518, 520,522, 524. SDO entries (3xyz), however, are unique for each module 512,514, 516, 518, 520, 522, 524 as a result of the application specificnature of built in self test (BIST) data objects.

Messages of the type mentioned above are transmitted and received usingmessage frames, such as the message frame 586 shown in FIG. 37. Thestructure of the message frames is a function of software executed byeach module and configured for operation with various 8-bit 8051 familymicroprocessors. As already indicated, in one embodiment the softwareconforms to CANopen protocol for the application layer of network 510.As shown in FIG. 36, frame 586 includes seven different bit fieldsincluding start of frame (SOF) field 588, arbitration field 590, controlfield 592, data field 594, CRC field 596, acknowledge field 597, and endof frame (EOF) field 598. SOF field 588 indicates the beginning ofmessage frame 586. Arbitration field 590 includes an 11-bit baseidentifier, and an 18-bit identifier extension. Together, theseidentifiers provide the message identifier introduced above. Theidentifier also determines the priority of the message for use inresolving bus access competition between or among modules 512, 514, 516,518, 520, 522, 524 according to a non-destructive, contention-basedarbitration scheme. This scheme, as is well-known in the art, ensuresthat messages are sent in order of priority, and that the content ofeach message is preserved. Arbitration field 590 further includes asubstitute remote request bit that is transmitted as a recessive bit andused to resolve priority conflicts between different frame formats.Control field 592 includes six bits: two reserved bits (r0 and r1) and afour bit data length code (DLC) indicating the number of bytes in datafield 594 that follows. Data field 594 may contain up to eight bytes ofdata. CRC field 596 includes a 15-bit cyclical redundancy check code anda recessive delimiter bit. Acknowledge field 597 includes two bits: aslot bit which is transmitted as recessive but is subsequently overwritten by dominant bits transmitted from any module 512, 514, 516, 518,520, 522, 524 that receives the transmitted message, and a recessivedelimiter bit. Finally, EOF field 598 consists of seven recessive bits.After each message frame 586, an intermission field 599 is provided thatincludes three recessive bits. Thereafter, the bus is considered idle.

Linear actuators driven by DC brush motors are commonly used to performraising and lowering movements (e.g., head, foot, hi/lo, knee, leg) ofdeck sections on hospital beds. For example, see U.S. Pat. Nos.5,918,505; 5,939,803; and 6,158,295, all of which are assigned to LinakA/S of Denmark. In the hospital room environment, product safety is animportant concern. DC motors used in hospital beds are configured tooperate safely in the medical environment.

As discussed above, control system 44 includes logic module 512. Inaddition to other functions, logic module 512 includes a drive controlsystem 601 which controls the DC motors 604 of linear actuators 48 usedto articulate deck sections 38, 40, 42 of patient support 10.

Drive Control System

FIG. 38 illustrates an embodiment of drive control system 601. Asillustrated, each actuator 48 includes a drive motor 604 and a positiondetector 606. Actuator 48 is electronically coupled to a power source612, such as a primary power source coupled to AC plug connection 45 orbackup power source or battery 46, and a microcontroller 614.

Microcontroller 614 includes memory 616, timer 618, analog-to-digitalconverter 620 and central processing unit (CPU) 622. Illustratively,timer 618 may include a single system clock 624 coupled to the CPU 622and/or a plurality of application timers 625 a, 625 b, . . . , 625 n, asneeded to execute the various features of drive control system 601. Ingeneral, application timers 625 a, . . . 625 n are incremented at a ratewhich is a function of the system clock 624 of CPU 622, as is wellknown.

The above-mentioned components of drive control system 601, e.g.,actuators 48, power source 612, and microcontroller 614 are well-knownand one of ordinary skill in the art would readily be able to select theappropriate models and/or types of such components as needed to operatethe articulation functions of patient support 10. For example, memory616 includes volatile (e.g., flash memory, RAM) and non-volatile (e.g.,on-chip EEPROM) memory for storing computer programming code and datarequired by control system 601. In the illustrated embodiment, on-chipEEPROM memory is used for long term data storage while flash basedmemory is used for storage of computer programming code and RAM memoryis used for short term data storage, however, it is understood thatother suitable memory configurations would work equally as well.

Embodiments of drive control system 601 include one or more of thefeatures described below.

End of Travel Control System

In an illustrative embodiment, linear actuators 48 including DC drivemotors 604 are used to drive the movement of head, seat, and legsections 38, 40, 42 of patient support surface 10. In general, actuators48 are activated by activation by a caregiver or patient of one or moreof the control buttons illustratively located on controllers 50, 52, 54(e.g., buttons 1520, 1522 on detachable siderail controller 50; buttons1550, 1551, 1564, 1566, 1574 on first siderail controllers 52; buttons1628, 1624, 1626 on controllers 54) or one or more of the pedals of thefoot pedal controls 56. As common with most linear actuators, failure ofany of actuators 48 may occur if a drive or rod reaches its mechanicalend of travel, for example, due to a heavy load on the actuator.

It is known to provide an actuator with an electrical end of travel thatis defined to occur earlier than the mechanical end of travel to preventthe actuator from reaching its mechanical end of travel. Using theelectrical end of travel, a loss of current occurs when the drivingcomponent, such as a piston rod moves past the electrical end of travel.Many existing drives operate until the electrical end of travel isreached. However, in patient support surfaces such as hospital beds,reaching even the electrical end of travel may cause the drive to bounceback and forth due to hysteresis of the drive mechanism. Suchoscillatory motion or bouncing may present a safety concern,particularly in drives used to raise and lower the head section of thepatient support surface and in drives that power the hi/lo mechanism.

To prevent the above-described oscillatory motion or bouncing in patientsupport 10, some or all of linear actuators 48 are coupled to a closedloop end of travel control system 626, which establishes a new end oftravel setting and thus prevents the actuator from reaching either theelectrical or mechanical end of travel during articulation of a sectionof patient support 10. In the illustrated embodiment, at least headsection actuator 48 c and deck actuators 48 a, 48 b are coupled tocontrol system 626.

Another application of end of travel control system 626 relates to theCPR function of the illustrative embodiment patient support 10. Asdescribed above, when CPR handle 352 is activated by a caregiver oroperator of patient support 10, head section 38 is mechanically lowered.Also, the actuator 48 d for seat section 40 is automatically activatedas needed to lower seat section 40 and the actuator 48 e for leg section42 is automatically activated as needed to raise leg section 42, to putpatient support 10 into the horizontal position shown in FIG. 3. End oftravel control system 626 operates to detect when head section 38, seatsection 40 and leg section 42 have reached their respective bottom orzero positions, shown in FIG. 3. Upon detection of the bottom positionof head, seat and leg sections 38, 40,42, a timer is started. If thecaregiver/operator continues to keep CPR handle 352 activated for apredefined period of time, patient support 10 is automatically movedinto the emergency Trendelenburg position shown in FIG. 9. If CPR handle352 is released before the predefined wait period expires, patientsupport 10 does not continue into the emergency Trendelenburg position.In this way, a “single action” CPR handle for moving patient support 10into the CPR and emergency Trendelenburg positions is provided.

Closed loop end of travel control system 626 of the illustrativeembodiment is provided in addition to any other electrical andmechanical end of travel systems. However, it is understood that inother embodiments, closed loop end of travel control system 626 may beprovided in lieu of traditional end of travel systems.

Linear actuators 48 a, 48 b, 48 c, 48 d, 48 e, 48 f are shown, forexample, in FIGS. 7 and 18. Each actuator 48 includes DC drive motor 604that powers linear movement of respective piston rod 172, as is wellknown in the art. In FIG. 38, it is shown that as drive motor 604 movespiston rod 172 including load connector 628 in the direction of arrow629, it approaches a mechanical end of travel. The closed loop end oftravel control system 626 includes a built-in feedback mechanism thatcontinuously monitors the actual position 630 of piston rod 172 andcompares the actual position 630 to a new predetermined end of travellimit 632. The new end of travel limit 632 is set to occur earlier thaneither the electrical end of travel 634 or the mechanical end of travel636 of the actuator 48, so that it will be reached before either theelectrical or mechanical end of travel 634, 636. Movement of the rod 172is limited to the predetermined end of travel limit setting 632 toprevent oscillating or bouncing and to prevent rod 172 from reachingmechanical end of travel 636.

In the illustrated embodiment, position detector 606 is a potentiometerlocated inside the housing of drive motor 604, however, it is understoodthat other means for detecting position, such as a tachometer, may beused. For actuators 48 that are provided with end of travel controlsystem 626, potentiometer 606 has a predetermined setting approximatelyequal to new end of travel limit 632. Calculation of new end of travellimit 632 is discussed below. Position detector 606 measures the currentposition 630 of rod 172 and compares it to new end of travel limit 632.If the actual position 630 reaches new end of travel limit 632, an errormessage or message indicating that the limit has been reached is sent tomicrocontroller 614, and subsequent actions are taken as describedbelow.

In certain embodiments of end of travel control system 626, timer 618includes an application timer 625 a that is programmed by software totime the operation of drive motor 604, e.g., to track the time ofoccurrence of each measured position 630, as described below. Each timedrive motor 604 starts, whether to perform an up or down/forward orbackward motion, timer 625 a is started. When drive motor 604 stops,timer 625 a stops. Position information 630, 632, 634, 636 and time ofoccurrence information are stored in memory 616.

FIG. 40 shows steps performed in the method of operation of end oftravel control system 626 when a drive motor 604 is operating. Beginningat step 646, a current position 630 of the drive rod 172 during itsoperation is determined. For each actuator 48, the process associatedwith control system 626 identifies a known “initial” position of thedrive rod 172. In the illustrated embodiment, the initial position ofthe drive rod 172 is the unextended position, but it is understood thatany drive position could be designated as the initial position. Theinitial position may be different for each drive actuator 48. Theinitial position for each actuator 48 is obtained by measuring thevoltage across potentiometer 606 in a voltage divider circuit andconverting the measured value to digital form using A/D converter 620.The potentiometer 606 reading is representative of the movement of thedrive shaft or rod 172 of drive motor 604.

Based on the potentiometer 606 reading at the initial position of eachdrive rod 172 and the total stroke length of the drive rod 172(typically provided by the drive manufacturer), a correlation can bemade between the potentiometer 606 reading and the stroke length (e.g.,with stroke length illustratively measured in millimeters). In this way,current position 630 of drive rod 172 during its travel is determined bycomparing the current potentiometer 606 reading to a table of knownpotentiometer readings and the corresponding stroke length for drive rod172.

Typically, actual position 630 is measured on a recurring basis overpredefined time intervals, such as every 20 milliseconds, as counted bytimer 625 a. In other embodiments, the time that position 630 ismeasured is also captured. In the illustrative embodiment, if rod 172 istraveling upward, the last position captured before current position 630is kept in memory and used as detailed below. It is understood that thelast position could be tracked during upward, downward, forward, and/orbackward movement as needed. The last position, and current position630, along with sample times associated with each of the last positionand current position 630, are converted to digital form by A/D converter620 and stored in memory 616.

At step 648, new end of travel limit 632 is determined in the mannerdescribed above, e.g., based on the potentiometer 606 value when the rod172 is in the extended position. For example, in one embodiment, alook-up table stored in memory 616 is used. In another embodiment, limit632 is calculated based on the anticipated amount of hysteresis ofactuator 48. The anticipated amount of hysteresis can be estimated as apercentage of the total stroke length of drive rod 172. In theillustrative embodiment, the amount of hysteresis is estimated as about1% or less of the total stroke length, however, it is understood thatother suitable methods for calculating anticipated hysteresis may beused, depending on the particular type or model of drive actuator 48being used and/or its particular application. New limit 632 isdetermined, for example, by adjusting electrical end of travel limit 634by the anticipated amount of hysteresis, so that new limit 632 occursearlier than electrical limit 634. New limit 632 may also be based onthe height of patient support 10 and/or the angle of head section 38and/or system level noise. For example, in the illustrated embodiment,new limit 632 is calculated assuming a bed height of approximately 36centimeters and 65-75 degrees of head angle. It is understood that thevalues obtained for limits 632 and 634, stroke length, and estimatedamount of hysteresis are stored in memory 616 as needed to perform theabove-described calculations.

At step 650, the change in position of rod 172 is analyzed. Currentposition 630 is compared to limit 632 using computer programming logic.In additional embodiments, a rate of change of position of rod 172, isdetermined by comparing the time of measurement of current position 630to the previously measured current position and its time of measurement.

It is understood by those skilled in the art that the rate of change ofposition of rod 172 is determined based on the position readings ofpotentiometer 606 and is also affected by the drive's spindle pitch.Speed and pitch data for the drive are generally provided by themanufacturer.

The rate of change of position is monitored, for example, to determinewhether the drive is overloaded or whether something is interfering withthe portion of the bed being moved by the drive. For instance, if apatient is attempting to raise the head end of the bed, but does notrealize that the frame is caught on something, such as a window sill,the rate of change of position analysis will indicate that though thedrive is running, the position has not changed as normal. As a result,an error code is generated and the motor shuts down to avoid furtherdamage to the system or harm to the patient.

At decision step 652, actual position 630 is compared to limit 632.Additionally, the rate of change of position is compared to apredetermined rate of change position limit 653 stored in memory 616. Ifthe actual position 630 of rod 172 has not reached limit 632, or if theactual rate of change of position has not reached the rate of change ofposition limit 663, then the process returns to step 646.

The illustrated embodiments are particularly concerned with monitoringupper position and rate of change of position limits, however, it isunderstood that in alternative or addition, lower limits may also bedefined and controlled in similar fashion.

If actual position 630 has reached or exceeded limit 632, or if theactual rate of change of position has reached or exceeded the rate ofchange of position limit 653, then at step 664 potentiometer 606 sends afault condition or “limit reached” signal to microcontroller 614.

At step 656, microcontroller 614 handles the fault or limit reachedcondition. In certain embodiments, if position limit 632 is reached orexceeded, or if the rate of change of position limit 661 is reached orexceeded, microcontroller 614 recovers from the error condition byinitiating application code, e.g., via a software process or internal orexternal reset, which resets position 632 to a zero or home position andrequests actuator 48 to begin motion in the opposite direction. Forinstance, if limit 632 is reached during downward travel, position 632is reset to zero and a signal to begin travel in the upward direction isissued. The process would occur in reverse, if the actuator 48 wasmoving in the opposite direction.

In other embodiments, at step 656, if position limit 632 is reached orexceeded, or if the rate of change of position limit 663 is reached orexceeded, microcontroller 614 places patient support 10 in a safe/errorstate that minimizes hazards to patients, caregivers, associatedindividuals, equipment, and/or data. For instance, microcontroller 614may initiate a reset or signal power source 612 to interrupt, disengage,or reduce current supplied to actuator 48.

At step 656, microcontroller 614 may also set a flag to indicate to anoperator that service is necessary on the affected actuator 48 or on theentire drive system. Such indication may be communicated to an operatorby illuminating, blinking or flashing one or more LEDs located on one ofcontrollers 50, 52, 54, or other suitable location on patient support10. Different colored LEDs may be used to signal different types oferrors. In the illustrated embodiment, red, green, and amber coloredLEDs are used. For example, if the position 630 of actuator 48 c of headsection 38 has exceeded limit 634, red and green LEDs may be set toblinking while an amber LED remains off. However, it is understood thatany suitable combination of colors and LED activity may be used toindicate the various possible error types. Further, other conventionalalarm devices may be utilized such as audible buzzers or bells.

As discussed above, the rate of change of position is monitored todetect whether the drive actuator 48 is overloaded or when aninterference condition exists, for example, if drive motor 604 ispowered on to raise a deck section 38, 40, 42, but something, such as awindow sill, piece of equipment, or utility cart, interferes with itsmovement or there is excessive weight on the deck section. The rate ofchange of position is determined using a potentiometer 660 or by othersuitable means known in the art. In the illustrated embodiment,potentiometer 606 is used to determine the rate of change of position bymeasuring the rate of change of the position of drive rod 172 over time.If the rate of position change is too high or too low, an overload orinterference condition is detected. In the illustrated embodiment, “toohigh” or “too low” means that the rate of position change is at leastapproximately 200% above or below the normal operating rate of change ofposition of drive 48 when actuated by a user (i.e., the normal rate whenan “up” or “down” button is pressed to raise or lower a bed section). Ifan overload or interference condition is detected, based on comparisonof rate of change of position to rate of change of position limit 653,an error code will be generated at step 654 and the error condition willbe handled at step 656 as described above.

Duty Cycle Protection

For safety and warranty reasons, linear actuator drive manufacturerstypically set a maximum run time for their actuators. Typically, themaximum run time is specified in terms of minutes per hour, e.g., 6minutes per hour. In view of the safety concerns of the medicalenvironment, a reliable mechanism is needed to detect in a preventativeway when an actuator's run time is approaching the predefined run timelimit to prevent thermal overload of the actuators, protect againstoveruse of the actuators, and prolong the life of the actuators. Thus,in certain illustrative embodiments of the present invention, logicmodule 512 of control system 44 includes a closed loop control circuit660 that monitors both current and drive run time. Duty cycle protectioncircuit 660 measures the actual run time of an actuator 48 and thenprevents drive operation if a maximum run time 662 is exceeded, asdescribed below. Circuit 660 is designed to prevent thermal protectioncircuit 670 (described below) from experiencing a fault condition.

FIG. 40 shows an illustrative embodiment method of operation of dutycycle protection circuit 660. At step 688, system 660 detects whetherone or more actuator motors 604 are running, e.g., by detecting a signalfrom a motor sensor 546 or detecting that a signal to start one or moreof actuators 48 has been received. In the illustrated embodiment, thisoccurs when any of the articulation control buttons (e.g., head upbuttons 1551, 1520, head down buttons 1550, 1522, tilt button 1564,reverse tilt button 1566, etc.) of controllers 50, 52, 54 are activated(i.e., pressed by a patient or caregiver). Also, in the illustratedembodiment, articulation of a bed section will typically occur inresponse to activation of a control button for as long as the controlbutton remains activated (until the travel limit is reached). If thepatient or caregiver releases pressure from the control button,articulation will stop until the same button is pressed again, oranother articulation button is activated. In alternative embodiments, asingle press of an articulation button activates the articulationfunction, and a second press deactivates the articulation function.

If an articulation signal has been received, process 660 proceeds tostep 690. At step 690, microcontroller 614 determines which actuators 48a, 48 b, 48 c, 48 d, 48 e, 48 f have been activated, e.g., by referenceto the correspondingly activated control button and the associatedarticulation function. For example, if head up button 1551 is activated,then head section actuator 48 c is actuated. The maximum run time 662 isdetermined for the activated actuators 48 and stored in memory 616. Themaximum run time may 662 vary depending on the particular actuator modelused and/or its particular application. As mentioned above, the maximumrun time 662 is typically defined by the manufacturer of the actuator.For example, for linear actuator model LA28, made by Linak A/S, themaximum run time is currently stated as 10% or 6 minutes per hour atcontinuous use. In the illustrative embodiment, the duty cycles ofactuators 48 range from 20% to 80%, however, it is understood that theduty cycle for a suitable actuator may fall outside this range. Further,it is understood that other methods of determining maximum run time maybe used, for example, depending upon the particular function to whichactuator 48 is assigned.

At step 692, an application timer 625 b for circuit 660 is started, inorder to keep track of how long motor(s) 604 of activated actuator(s) 48are running. At step 694, the actual current 668 is measured using anammeter or other suitable means known in the art. Run time 666 istracked by timer 625 b.

At step 696, measured current 668 and run time 666 are analyzed bymicrocontroller 614. In the illustrated embodiment, run time 666 isevaluated by using an analysis of the rate of heat transfer in drivemotor 604. It is known that as current increases, temperature increases,and that the rate of heat transfer is a function of conductivity andtemperature gradient. Thus, the rate of heat transfer can be assessedbased on the change in current 668 over time.

Before drive motor 604 has started running, e.g., when patient support10 is first plugged in, run time 666 (e.g., the count of timer 625 b) isinitialized or set to zero. While drive motor 604 is running, timer 625b is incremented by a predefined amount which is based on the measuredcurrent 668. If current 668 is high, timer 625 b will be incremented bya greater amount, and if current 668 is low, timer 625 b will beincremented by a lesser amount. In the illustrated embodiment, differenttime increments are specified for four different ranges of current,e.g., timer 625 b is incremented by 12, 14, 16 or 18 counts based on theamount of current 668 being drawn by drive motor 604.

If drive motor 604 stops running, timer 625 b is decremented by a value“L” representative of the rate of heat transfer based on the knownthermodynamics equation, q=−KΔT, where q is the rate of heat transferper unit area, ΔT is the temperature gradient, and K is conductivity.The higher the level of the value of timer 625 b, the greater the value“L” will be. In the illustrated embodiment, L is 1, 2, or 4 depending onhow high timer 625 b has been incremented.

If drive motor 604 is disconnected from power source 612, run time 666(e.g., the count of timer 625 b) is stored in memory 616. In this way,system 660 accounts for the fact that drive motor 604 may not have beendisconnected from power for a significant time.

At decision step 698, if the drive run time 666 reaches or exceeds thepredetermined run time threshold 662, the process proceeds to step 702.In the illustrated embodiment, this is determined by comparing the countof timer 625 b (i.e., run time 666) to maximum run time 662.

At step 702, a fault condition is signaled and, at step 704, the currentmotor function (e.g., chair head up, head down, etc.) is deactivated orturned off. Also at step 702, logic may be used to allow certainemergency functions, such as CPR, to be activated prior to turning offthe current motor function. For example, in the illustrated embodiment,CPR mode can still be activated at least one time after system 660detects a duty cycle overrun. In response to a fault condition,microcontroller 614 may place patient support 10 in a “safe state” thatminimizes hazards to patients, caregivers, associated individuals,equipment, and data, e.g., by signaling power source 612 to interrupt,disengage, or reduce current supplied to drive motor 604 of theactivated actuator 48. Microcontroller 614 may also activate an audibleor visual indicator to alert an operator that service is necessary onthe affected drive or on the entire system. Such indication may becommunicated to an operator by, for example, illuminating, blinking orflashing one or more LEDs located on one of controllers 50, 52, 54, orother suitable location on patient support 10.

At step 708, a timer 625 c is started, which counts off a predefinedwait period after which it is safe to restart the previously operatingmotor function. The wait period may be determined based on the value ofrun time 666 or maximum run time 662, or other criteria. For example,the wait period may be set equal to the maximum run time 662. In theillustrated embodiment, the wait period is set equal to half of themaximum run time 662.

At decision step 710, microcontroller 614 determines whether the waitperiod has expired. Step 710 is repeated until the wait period hasexpired. In the illustrated embodiment, when the wait period hasexpired, the motor function is restarted at step 712. However, it isunderstood that in other illustrative embodiments, it may not benecessary or desirable to restart the motor function and thus step 712may be eliminated in those embodiments.

Returning to step 698, if run time 666 has not reached or exceededmaximum run time 662, the process proceeds to decision step 700. At step700, system 660 determines whether drive motor 604 of the activatedactuator 48 is still operating, e.g., by detecting a signal from a motorsensor 546 or by checking to see if one of the corresponding controlbuttons is activated. If the activated actuator 48 is still running, theprocess returns to step 694 to measure current 668 and run time 666. Ifactuator 48 is not still running, the process ends at step 706.

Thermal Protection

To protect DC drive motors 604 from thermal overload during use in ahospital room environment, a method 720 for detecting thermal failure ofthe drive motors 604 is provided. A thermal overload condition can occurif, for example, failure of the current overload,interference/obstruction detection, or duty cycle protection mechanismsdescribed above occurs. The presently described method 720 is adapted tothe specific safety risks of a medical environment. An embodiment of themethod is shown in FIG. 42.

At step 722, a maximum temperature 723 is determined for a drive motor604 of a selected actuator 48. Maximum temperature 723 is typicallydetermined by reference to the manufacturer's specifications for theparticular actuator 48. However, it is understood that other means fordetermining maximum temperature 723, including experimentation, forexample, under particular environmental conditions, may be used. Maximumtemperature 723 is stored in memory 616.

Typically, activation of a selected actuator 48 occurs when a patient orcaregiver selects the corresponding actuator control button oncontroller 50, 52, or 54, as described above. During operation of theselected actuator 48, a current temperature 724 of the drive 604 ismeasured inside the housing of drive motor 604, at step 726. Anysuitable thermal sensing element, such as a conventional thermocouple,may be used to measure temperature 724. An application timer 625 d isused to periodically sample temperature 724 during operation of actuator48 as long as the drive is in operation and maximum temperature 723 hasnot been exceeded. Temperature 724 is converted to digital form by A/Dconverter 620 and is stored in memory 616.

At step 728, the temperature of drive motor 604 is analyzed. Currenttemperature 724 is compared to maximum temperature 723. At decision step730, microcontroller 614 determines whether operation of actuator 48should continue in view of current temperature 724. If currenttemperature 724 reaches or exceeds maximum temperature 723, the process720 continues to step 732, where an error signal is generated. Ifcurrent temperature 724 is less than maximum temperature 723, theprocess 720 returns to step 726.

At step 732, a fault condition is signaled and, at step 734,microcontroller 614 places patient support 10 in a safe state thatminimizes hazards to patients, caregivers, associated individuals,equipment, and data, e.g., by signaling power source 612 to interrupt,disengage, or reduce current supplied to drive motor 604 of theactivated actuator 48. Microcontroller 614 may also set a flag toindicate to an operator that service is necessary on the affected driveor on the entire system. Such indication may be communicated to anoperator by illuminating, blinking or flashing one or more LEDs locatedon one of controllers 50, 52, 54, or other suitable location on patientsupport 10. In the illustrated embodiment, if measured temperature 724exceeds maximum temperature 723, thermal failure is assumed and thedrive 604 is automatically shut down. Typically, a bimetallic thermalswitch located inside the motor housing opens to interrupt the currentsupply to drive 604.

Patient support surfaces, such as hospital beds, often include manyfeatures that are electrically powered. Such features include bedarticulation controls that allow the various deck sections of the bed tobe raised or lowered so that the bed can support patients in a number ofdifferent positions. There is a need for at least some of these bedcontrols to remain available when the bed's primary source of power islost, i.e., due to a power outage, or while a patient is beingtransported from one hospital room to another.

Battery Backup System

As a result of government regulations that, for example, requirehospital beds to be able to assume the emergency Trendelenburg positionwhether or not AC power is available, and for other reasons, existinghospital beds may include a battery backup system that powers the bedfunctions when AC power is not available. However, because hospital bedsoften require a substantial amount of power to operate the variousfeatures, a method to conserve battery power while maintainingcompliance with existing regulations is desired.

As best shown in FIG. 31, frame 12 supports a battery enable switch 736.Battery enable switch 736 is a normally open contact, momentary functionswitch. In the illustrated embodiment, battery enable switch 736 islocated on the portion of base frame 28 that is substantially underneathhead section 38 of deck 26, however, it is understood that batteryenable switch 706 could be located anywhere on base frame 28 or otherarea of patient support 10 as necessary or convenient. Battery enableswitch 736 is electrically coupled to a battery 46, shown in FIGS. 2 and31.

Battery enable switch 736 allows a person, such as a health careprovider, to operate electrically-controlled bed functions (such as bedarticulation functions) of patient support 10 using a backup powersource (in the illustrated embodiment, battery system 46) when theprimary power source 738 (e.g., AC power coupled to bed 10 by plugconnection 45) is not available. Such instances may occur, for example,when a power outage occurs or when a bed 10 is being moved from one areaof a hospital to another.

As shown in FIG. 31, battery enable switch 736 is a momentary switch,such as a push button. Switch 736 includes a light-emitting diode (LED)737 or other suitable illuminating means known in the art, enclosed inor covered by a translucent or transparent housing made of plastic orother suitable material. The LED 737 is illuminated when either primarypower source 738 is coupled to bed 10 through plug connection 45, orbackup power or battery 46 is charged and supplying power to bedfunctions of patient support 10. When patient support 10 is disconnectedfrom primary power source 738, or if backup power source 46 isdischarged, the LED 737 is not illuminated. If primary power source 738is disconnected and backup power source 46 is in need of power or isrecharging, the LED 737 blinks or flashes intermittently on and off.

Circuitry for controlling the activation of backup power source 46 isincluded in control system 44. As illustrated in FIG. 43, primary powersource 738 is connected to switching regulator 740 through diode 742 andconnection 744. Backup power source 46 is connected to switchingregulator 740 via connection 746, contact 748 of relay 750, diode 752and connection 744. Switching regulator 740 provides power to at leastthe electrically-controlled bed functions that are required or desiredto operate under backup power, such as bed articulation functions.

Relay 750 includes contact 748 and coil 754. When primary power source738 is operating, voltage is applied to switching regulator 740 throughconnection 744 and to microprocessor 756 through connection 758. Whenvoltage is not present on connection 758, microprocessor 756 senses thelack of primary power and closes contact 748 of relay 750 by energizingcoil 754. Closing relay contact 748 provides sufficient backup power tothe bed for a predetermined amount of time to allow an orderly shutdownof the bed functions. After the predetermined period of time expires,microprocessor 756 opens relay contact 748 to remove logic power fromthe bed functions and put patient support 10 into sleep mode.

When patient support 10 is in sleep mode, activation of battery enableswitch 736, e.g., by momentarily pressing switch 736, causes patientsupport 10 to switch out of sleep mode. Activating switch 736 whileprimary power source 738 is operating has no effect.

In the illustrated embodiment, battery enable switch 736 is activated bythe application of pressure on the housing, i.e., by depressing switch736 with one's finger. In other embodiments, activating any one of thebed function control buttons located on controllers 50, 52, 54 whilepatient support 736 is in sleep mode will also switch it out of sleepmode.

When switch 736 is activated, sufficient power is provided from backuppower source 46 so that at least certain required electricallyoperational functions of patient support 10, such as articulation ofpatient support 10, can be performed. In the illustrated embodiment,activation of switch 736 selectively powers certain bed functions,including the bed articulation functions, while other features, such asscale/ppm module 516 and dynamic surface module 518, are not powered bybackup power source 46 in order to conserve power. Also, power is alwaysprovided to nurse call control 570, even when backup source 46 is insleep mode. It is understood however, that control system 44 may beconfigured so that any particular combination of electrically-controlledfeatures of patient support surface 10 (including scale/ppm module 516and/or dynamic surface module 518) may be powered by backup power source46.

When microprocessor 756 detects that no power is being supplied byprimary power source 738, pressing switch 736 causes microprocessor 714to apply voltage from backup power source 46 to energize relay coil 754and close relay contact 748. Closing relay contact 748 again provideslogic power to bed functions via switching regulator 740 and Vcc powerto microprocessor 756. When microprocessor 756 receives power Vcc, itactivates a transistor 760 through connection 762. Microprocessor 756includes a timer and holds transistor 760 in an on or activated statefor a predetermined period of time, as further explained below. When thepredetermined period of time expires, microprocessor 756 turns off ordeactivates transistor 760. Turning off transistor 760 shuts off logicpower to the bed electronics, thus saving battery power.

FIG. 44 shows a flow diagram of an embodiment of the logic processencoded in microprocessor 756. At decision step 770, microprocessor 756determines whether primary power source 738 is available. If primarypower source 738 is operating, then normal power continues to beprovided to the bed functions via primary power source 738, at step 771.Also, while primary power source 738 is operating, backup power source46 is continuously charging as necessary.

If microprocessor 756 senses that primary power source 738 is notoperating, electrically-controlled functions of patient support 10 areput into sleep mode as described above, at step 772.

At step 774, microprocessor 756 monitors the system to detect whether abed function is activated or whether battery enable switch 736 isactivated, e.g., by pressing a control button, key or switch. If no suchfunction has been activated, microprocessor 756 returns to step 770,checks to see if primary power source 738 is available yet, andthereafter continues to either step 771 or 772 as described above.

If a key has been pressed, microprocessor 756 determines if backup powersource 46 is sufficiently charged to provide power to the bed functions,at step 776. If backup power source 46 is in need of recharging, the LED737 of battery enable switch 736 will begin flashing as described above,at step 778. If backup power source 46 is sufficiently charged, relay750 is closed so that bed functions can be activated using backup powersource 46, as described above, at step 780.

As mentioned above, microprocessor 756 includes a timer. At step 782,when backup power 46 is activated, microprocessor 756 sets the timer tocount until one of the following occurs: a bed function control buttonis depressed, battery enable switch 736 is depressed, or a predeterminedamount of time (e.g., 5 minutes) elapses. It is understood that indifferent embodiments, less than all of these conditions may be tested.For example, in one embodiment, pressing battery enable switch 736 maynot interrupt the timer.

At step 784, microprocessor 756 determines whether the preset amount oftime has elapsed. If the predefined time period has elapsed, the processreturns to step 772, where the bed functions are put into sleep mode. Ifthe time period has not elapsed, microprocessor 756 checks to see ifanother key (e.g., a bed function-activating key or the battery enableswitch) has been pressed, at step 786. If no key has been pressed, thetimer continues counting until the predetermined time period expires, atstep 784.

If another key has been pressed, as determined at step 786, then thetimer is reset at step 788. The process then returns to step 780 andbackup power source 46 is reactivated or awakened out of sleep mode.

In this manner, backup power is conserved and, in embodiments where abattery 46 is used to support backup power system, a smaller battery canbe used. At the same time, battery enable switch 736 permits patientsupport 10 to meet the above-mentioned regulatory requirements byenabling at least a portion of the bed's articulation features to beoperable on backup power when needed.

Siderails and Headboard

Head and foot end siderails 20, 22 are configured to move between upperpositions, as shown in FIGS. 1, 45, and 46, and lower positions, asshown in FIG. 47, to permit entry and egress of patients into and out ofpatient support 10. Head end siderails 20 are coupled to head section 38and may be moved between raised and lowered positions. Foot endsiderails 22 are coupled to weigh frame 36 and may also be moved betweenraised and lowered positions.

As head section 38 of deck 26 rotates relative to weigh frame 36, headend siderail 20 also rotates relative to weigh frame 36. However,regardless of the movement of sections 38, 40, 42, foot end siderails 22do not move relative to weigh frame 36.

Siderails 20 include rail members 1110 and linkage assemblies 1114coupled between rail members 1110 and head section 38 of deck 26 thatpermits rail members 1110 to be moved between upper and lower positions.Siderails 22 include rail members 1112 and linkage assemblies 1116coupled between respective rail members 1112 and weigh frame 36 thatpermits rail members 1112 to be moved between upper and lower positions.

As shown in FIGS. 45 and 48, linkage assembly 1114 of head end siderail20 includes a first link 1118 rigidly coupled to head section 38, a pairof curved second links 1120 pivotably coupled to first link 1118, athird link 1122 pivotably coupled to second links 1120, and a curvedfourth link 1124 pivotably coupled to third and first links 1122 and1118. First link 1118 includes a pair of first flanges 1126 welded tohead section 38 and a pair of second flanges 1130 welded to head section38. Each second link 1120 includes a looped first end 1132 pivotablycoupled to flanges 1126, 1130 by a rod 1134 and a looped second end 1136pivotably coupled to third link 1122 by a rod 1138, as shown in FIG. 48.

Third link 1122 includes a base plate 1140, a first pair of inwardlyextending flanges 1142 coupled to base plate 1140, and a second pair ofinwardly extending flanges 1144 also coupled to base plate 1140, asshown in FIG. 48. Rod 1138 extends between flanges 1142 and throughsecond ends 1136 of second link 1120 to provide the pivotable connectiontherebetween.

Referring to FIG. 49, fourth link 1124 includes a base 1146 and a cover1148 that together define a latch-receiving void 1150. A first end 1152of base 1146 is pivotably coupled to second pair of flanges 1144 ofthird link 1122 by a rod 1154. Similarly, a second end 1156 of base 1146is pivotably coupled to the lower ends of flanges 1130 of first link1118 by a rod 1158. Axial movement of each rod 1134, 1138, 1154, and1158 is prevented by a C-shaped or open retaining ring 1133 of the typeknown in the art. Thus, linkage assembly 1114 provides a four barlinkage permitting head end siderail 20 to swing between the upper andlower positions.

A biasing device 1125, illustratively a conventional gas spring, mayextend intermediate the first link 1118 and the fourth link 1124 inorder to assist in the raising and lowering of the siderail 20. A firstend 1127 of the biasing device 1125 is pivotably coupled to the rod1134, while a second end 1129 of the biasing device 1125 is pivotablycoupled to a connector 1131. The connector 1131 is illustrativelycoupled to the first end 1152 of the base 1146 of the fourth link 1124.The biasing device 1125 illustratively provides an upwardly acting forceto control the rate of descent of the siderail 20 and to assist thecaregiver 56 in raising the siderail 20.

Cover 1148 includes a pocket 1149 sized to receive a rectangular magnet1151 therein. Magnet 1151 is coupled to cover 1148 and rotates withfourth link 1124 during raising and lowering of head end side rail 20.Hall effect sensor 60 is coupled to flanges 1130 of first link 1118 androd 1134 to detect the position of magnet 1151. Based on this position,control system 44 knows when head end rail 20 is in the raised positionand the lowered position.

With reference to FIGS. 48-50, an electrical communication cord 1153extends into latch-receiving void 1150 under rod 1154 and is coupled tothird link 1122 by a cable tie 1155. Cover 1148 includes slits 1157configured to receive cord 1153 which extends into void 1150. A portion1159 of cord 1153 extends down into a pocket portion 1161 of void 1150to provide clearance for tabs 1163 of cover 1148 that snap intoapertures 1165 of base 1146.

As shown in FIGS. 49-50, cover 1148 includes a pin-receiving portion1167 positioned between pin-receiving portions 1169 of base 1146.Pin-receiving portion 1167 includes a notch or slit 1171 through whichcord 1153 extends from void 1150. As shown in FIGS. 49 and 50, base 1146further includes a plurality of notches 1173 having a width slightlysmaller than the diameter of cord 1153. Cord 1153 is positioned in thesenotches 1173 to limit movement of cord 1153 in void 1150.

Cord 1153 includes a portion or loop 1175 extending from notch 1171 tocable tie 1155. Portion 1175 is about three times as long as a distance1177 from cable tie 1155 to notch 1171. This additional length providesstress relief by reducing the amount of tension on cord 1153 andchaffing of cord 1153 during raising and lowering of siderail 20.

Referring to FIGS. 45 and 51, linkage assembly 1116 of foot end siderail22 is substantially similar to linkage assembly 1114 of head endsiderail 20. Linkage assembly 1116 includes a first link 1160 rigidlycoupled to weigh frame 36, pair of curved second links 1120 pivotablycoupled to first link 1160, third link 1122 pivotably coupled to secondlinks 1120, and curved fourth link 1124 pivotably coupled to third andfirst links 1122, 1160 as shown in FIG. 51.

First link 1160 includes a base 1162 coupled to weigh frame 36 byfasteners 1128 and having outer and inner pairs of upwardly extendingflanges 1164 a, 1164 b rigidly coupled to base 1162. Each second link1120 has its looped first end 1132 pivotably coupled to flanges 1164 a,1164 b of first link 1162 by rod 1134 and has its looped second end 1136pivotably coupled to flanges 1142 of third link 1122 by rod 1138. Firstend 1152 of base 1146 of fourth link 1124 is pivotably coupled toflanges 1144 of third link 1122 by rod 1154. Second end 1156 of base1146 is pivotably coupled to the lower ends of inner flanges 1164 b offirst link 1160 by rod 1158. The base plate 1140 of the third link 1122is coupled to the body of the rail member 1112. Axial movement of eachrod 1134, 1138, 1154 and 1158 is prevented by a C-shaped or openretaining ring 1133 of the type known in the art. Thus, linkage assembly1116 provides a four bar linkage permitting foot end siderail 22 toswing between the upper and lower positions.

Each siderail 20, 22 further includes a retainer 1166 configured to“bind” the four bar linkage to prevent siderails 20, 22 from moving fromthe upper position to the lower position. As shown in FIG. 49, retainer1166 includes a slide or handle member 1168 positioned in void 1150 toslide relative to base 1146 and cover 1148 of fourth link 1124 to movebetween a latched position, as shown in FIG. 52, and an unlatchedposition, as shown in FIG. 53, a pair of L-shaped rocker arms or members1170 pivotably coupled to base 1146, and a pair of latch members or pins1172 pivotably coupled to respective rocker arms 1170. Pins 1172 extendthrough apertures 1174 in base 1146 into apertures 1176 in respectiveflanges 1130, 1164 of respective first links 1118, 1160. Pins 1172include body members 1179 and head members 1181 inserted into bodymembers 1179.

Handle member 1168 includes a first end 1178 pivotably coupled to rockerarms 1170 and a second end or handle portion 1180 accessible from anhandle opening 1183 in base 1146 as shown in FIGS. 54 and 55. First end1178 includes a boss or lug 1182 positioned in slots 1184 defined inrocker arms 1170. A shoulder screw 1186 is provided to retain rockerarms 1170 on boss 1182. First end 1178 further includes a spring seat ormount 1188.

A spring 1190 is positioned in a spring-receiving channel 1192 definedby base 1146. Spring 1190 is positioned between spring seat 1188 and awall 1194 of base 1146 to bias handle member 1168 downwardly indirection 1196 (FIGS. 52 and 54). Because slide member 1168 is biased indirection 1196, pins 1172 are biased outwardly into apertures 1176 inrespective flanges 1130, 1164 of respective first links 1118, 1160. Whenpins 1172 are positioned in apertures 1176 of respective first links1118, 1160, respective fourth links 1124 are coupled together at twoaxially spaced apart locations. This prevents rotation of respectivelinkage assemblies 1114, 1116 to prevent siderails 20, 22 from swingingto the lower position.

To unbind linkage respective assemblies 1114, 1116 and permit respectivesiderails 20, 22 to swing to the down position, pins 1172 must be movedfrom the latched position (FIGS. 52 and 54) to the unlatched position(FIGS. 53 and 55). A caregiver can unlatch pins 1172 by pulling upwardlyon handle portion 1180 of slide member 1168 in direction 1198. Thismovement causes rocker arms 1170 to rotate about boss 1182 and pullspins 1172 inwardly out of apertures 1176 of respective first links 1118,1160 of linkage assemblies 1114, 1116 so that pins 1172 no longer bindsrespective first links 1118, 1160 and respective fourth links 1124.

Because respective first links 1118, 1160 and respective fourth links1124 are free to pivot relative to one another, respective linkageassemblies 1114, 1116 are also unbound and free to permit siderails 20,22 to swing between the upper and lower positions. According toalternative embodiments of the present disclosure, other retainers areprovided to hold the siderails in the upper position such as clasps,catches, locks, other latches, clamps, pins, bolts, bars, hasp, hooks,or other retainers known to those of ordinary skill in the art.

An alternative embodiment slide or handle member 1201 is shown in FIG.56. Handle member 1201 includes a bar member 1202 pivotably coupled torocker arms 1170 and a second end or handle portion 1203 coupled to barmember 1202 and accessible from handle opening 1183 in base 1146.Shoulder screw 1186 is positioned in slots 1184 defined in rocker arms1170 and is coupled to bar member 1202.

As shown in FIG. 1, when siderails 20, 22 are in upper position, railmembers 1110, 1112 block a patient's egress from patient support 10. Asshown in FIG. 19, siderail 22 and a lip or upper deck portion 263 ofdeck 26 cooperate to define a gap 1185 therebetween. According to anillustrative embodiment, gap 1185 is defined to be less than 60millimeters. Similarly, the gap between siderail 22 and deck 26 isdefined to be less than 60 millimeters.

FIG. 57 illustrates a patient support 10′ including alternativeembodiment siderails 20′, 22′ which are configured to move between upperpositions and lower positions to permit entry and egress of patientsinto and out of patient support 10′ in a manner similar to siderails 20,22. As such, siderails 20′, 22′ are substantially similar to siderails20, 22 and like reference numbers are used to identify like components.

Head end siderails 20′ are coupled to head section 38′ and may be movedbetween raised and lowered positions. Head board 16′ extends betweenhead end siderails 20′. Foot end siderails 22′ are coupled to weighframe 36 and may also be moved between raised and lowered positions.

Siderails 20′ include rail members 1110′ and linkage assemblies 1114coupled between rail members 1110′ and head section 38′ of deck 26′ thatpermits rail members 1110′ to be moved between upper and lowerpositions. Siderails 22′ include rail members 1112′ and linkageassemblies 1116 coupled between respective rail members 1112′ and weighframe 36 that permits rail members 1112′ to be moved between upper andlower positions.

As shown in FIG. 57, when siderails 20′, 22′ are in upper position, railmembers 1110′, 1112′ block a patient's egress from patient support 10′.As shown in FIG. 58, foot end rail 22′ includes a ridge or bump 1204coupled to rail member 1112′. Bump 1204 and a lip or upper deck portion263 of first leg section member 290 of leg section 42 of deck 26′cooperate to define a gap 1183′ therebetween. Bump 1204 reduces thewidth of gap 1183′. According to the present disclosure, gap 1183′ isless than 60 millimeters. Without bump 1204, gap 1183′ between first legsection member 290 and rail 1112′ would be wider than the gap betweensecond leg section member 292 and rail 1112′ because first leg sectionmember 290 is not as wide as second leg section member 292 as shown inFIG. 21. The gap between rail 1112′ and second leg section member 292 isalso less than 60 millimeters. The gap between rail 1110′ and deck 26′is also less than 60 millimeter.

As shown in FIG. 59, headboard 16′ includes a main body 1205 and a shelfor bump 1206 on each end of main body 1205. Headboard 16′ and head endsiderail 20′ cooperate to define a gap 1207 therebetween at each end ofmain body 1205. Each shelf 1206 narrow gaps 1207 near the top of headend siderails 20′ when siderails 20′ are positioned adjacent headboard16′. According to an alternative embodiment of the present disclosure, abump is provided on the footboard 18. According to another alternativeembodiment of the present disclosure, no bump is provided on theheadboard 16′.

Returning now to the illustrative embodiment siderails 20, 22 of FIGS.45-55, rail member 1110 of head end siderail 20 includes a main body1210, a cover 1212, and a brace 1214 (FIGS. 48 and 60). An O-ring seal1216 is provided between main body 1210 and cover 1212 to preventliquids from entering an interior region 1218 defined between main body1210 and cover 1212 as shown in FIGS. 60-62. Head end siderail 20further includes a water-proof speaker 1220 coupled to main body 1210that transmits sound through a plurality of slots 1222 defined in mainbody 1210.

Controllers

As discussed above, control system 44 is coupled to a first pair ofcontrollers or control panel 52 rigidly coupled to main body 1210, asecond controller or control panel 54 pivotably coupled to main body1210, and third detachable controller 50 that is removably received byhead and foot end siderails 20, 22 so that it can be removed from one offoot end siderails 22 and coupled to the other foot end siderail 22 orhead end siderails 20 to control various functions of patient support10. As described below, controllers 52, 54, 50 control various functionsof patient support 10 and are also configured to receive informationfrom a caregiver related to a patient and to send and receive patient orbed-related data to a central computer for storage, tracking, andanalysis.

Additional details of suitable electronics and other features ofcontrollers are provided in U.S. Pat. No. 5,715,548, titled “Chair Bed,”filed Aug. 4, 1995; U.S. Pat. No. 6,008,598, titled “Hand-HeldController For Bed and Mattress Assembly,” filed Apr. 22, 1998; U.S.Pat. No. 6,131,868, titled “Hospital Bed Communication and ControlDevice,” filed Jan. 1, 1997; and U.S. Provisional Application Ser. No.60/202,284, titled “Remote Control for a Hospital Bed,” filed May 5,2000, the disclosures of which are expressly incorporated by referenceherein.

Cover 1212 includes a plurality of apertures 1230 that match withcontrol buttons or switches 1232 of a circuit board 1233 of firstcontroller 52 that is coupled to cover 1212. The functions controlled byswitches 1232 will be described in greater detail below.

Second controller 54 includes a housing 1236 and a circuit board 1238including a plurality of control buttons or switches 1240 and an LEDdisplay 1242. Cover 1212 includes a pocket 1244 configured to receivecontroller 54 as shown in FIGS. 60 and 61. According to alternativeembodiments of the present disclosure, the display is an LCD, plasma, orother display known to those of ordinary skill in the art. The functionsof switches 1240 will be described in greater detail below.

Housing 1236 includes first and second housing shells 1246, 1248 thatcooperate to define a interior region 1250 sized to receive circuitboard 1238. Shells 1246, 1248 cooperate to define a boss or post 1252that is pivotably received in an aperture 1254 defined in cover 1212.Shells 1246, 1248 also cooperate to define an aperture 1256 sized toreceive a torsion spring 1258, a bushing 1260, and a pin 1262. To couplesecond controller 54 to cover 1212, post 1252 is inserted into aperture1254, and aperture 1256 is aligned with a corresponding aperture 1261 incover 1212. Pin 1262 is then inserted into aperture 1261 and aperture1256 to pivotably couple second controller 54 to cover 1212. Whencoupled, spring 1258 biases second controller 54 into pocket 1244.

This coupling allows the tilting of a lower edge 1264 of housing 1236upward thereby permitting a user to better see control buttons 1240.According to alternative embodiments of the present disclosure, otherconfigurations of couplers between the housing and the controller mountare provided. For example, hooks, hook-and-loop type fasteners, snaps, adetachable hinge, or other devices known to those of ordinary skill inthe art are provided to pivotably or otherwise couple the controller tothe siderail.

An electrical communication cord 1265 of controller 54 is coupled tocircuit board 1238 and extends from interior region 1250 defined byshells 1246, 1248 as shown in FIGS. 61 and 63. Post 1252 includes achannel or aperture 1253 through which cord 1265 extends. The channel iscentered on an axis of rotation 1263 of controller 54. During rotationof controller 54, a first end 1267 of cord 1265 rotates with controller54. However, a second end 1273 of cord 1265 coupled to circuit board1238 does not rotate. A portion 1277 of cord 1275 between first andsecond ends 1267, 1273 twists during rotation of controller 54 tocompensate for second end 1273 not twisting. Because cord 1265 extendsthrough post 1252, no portion of cord 1265 is positioned outside of theinterior regions 1218, 1250 of rail member 1110 and housing 1236.

Portion 1277 of cord 1265 extends from post 1252 to circuit board 1233and has a length that is about three times as long as a distance 1281from post 1252 to where it coupled to circuit board 1238. Thisadditional length reduces the amount of tension on cord 1265 andchaffing of cord 1265 during the pivoting of controller 54 about axis ofrotation 1263.

According to an alternative embodiment of the present disclosure, arubber grommet is provided in the channel 1253 to provide a liquid proofseal between cord 1265 and housing 1236. According to anotheralternative embodiment, a rubber grommet is provided between post 1252and cover 1212 to provide a liquid proof seal therebetween.

Referring now to FIG. 64, cord 1153 passes through fourth link 1124 tothird link 1122 in the manner detailed above. From behind third link1122, cord 1153 extends to and is coupled to circuit board 1233 ofcontroller 52. A cord 1271 extends from speaker 1220 of head endsiderail 20 and is also coupled to circuit board 1233 of controller 52.

Fluid Sealing

As described above, main body 1210 and cover 1212 of head end siderail20 are sealed together to prevent fluids from entering an interiorregion 1218 defined between main body 1210 and cover 1212. Main body1210 and cover 1212 include sealing edges 1268 and 1270, respectivelythat face each other when cover 1212 is coupled to main body 1210 (FIG.62).

With reference to FIGS. 60 and 64, sealing edge 1268 includes a firstportion 1272 that extends longitudinally and faces outwardly, a secondportion 1274 that extends laterally and faces toward a head end ofpatient support 10, a third portion 1276 that extends longitudinally andfaces outwardly, a fourth portion 1278 that extends laterally and facestoward a foot end of patient support 10, a fifth portion 1279 thatsubstantially vertically following a curved profile of a head end 1280of main body 1210 and faces outwardly, a sixth portion 1282 that extendsover a top end 1284 of main body 1210, a seventh portion 1286 thatextends longitudinally and faces inwardly, an eighth portion 1288 thatextends back over top end 1284 of main body 1210, a ninth portion 1290that follows a curved profile of a handle aperture 1292 defined in mainbody 1210 and faces outwardly, a tenth portion 1294 that extendssubstantially vertically following a curved profile of a foot end 1296of main body 1210 and faces outwardly, and an eleventh portion 1298 thatextends longitudinally and faces outwardly. Similarly, with reference toFIGS. 60 and 63, sealing edge 1270 includes a first portion 1310 thatextends longitudinally and faces inwardly, a second portion 1312 thatextends laterally and faces toward a foot end of patient support 10, athird portion 1314 that extends longitudinally and faces inwardly, afourth portion 1316 that extends laterally and faces toward a head endof patient support 10, a fifth portion 1317 that extends substantiallyvertically following the curved profile of head end 1280 of main body1210 and faces inwardly, a sixth portion 1318 that extends under ahooked or channel portion 1320 of cover 1212, a seventh portion 1322that extends longitudinally and faces outwardly, an eighth portion 1324that extends back under hooked portion 1320 of cover 1212, a ninthportion 1326 that follows the curved profile of handle aperture 1292 andfaces inwardly, a tenth portion 1328 that extends substantiallyvertically following a curved profile of foot end 1296 of main body 1210and faces inwardly, and an eleventh portion 1330 that extendslongitudinally and faces inwardly. The respective portions 1272, 1274,1276, 1278, 1279, 1282, 1286, 1288, 1290, 1294, 1298 of sealing edge1268 of main body 1210 face the respective portions 1310, 1312, 1314,1316, 1317, 1318, 1322, 1324, 1326, 1328, 1330 of sealing edge 1270 ofcover 1212.

Sealing edge 1268 includes a channel 1332 that extends along portions1272, 1274, 1276, 1278, 1279, 1282, 1286, 1290, 1294, 1296 of main body1210. See, for example, FIGS. 61 and 62, showing third portion 1276 andsixth portion 1286 having channel 1332 extending therethrough. O-ringseal 1216, made of rubber or other suitable material, is positioned inchannel 1332. When cover 1212 is positioned over main body 1210 of headend siderail 20, sealing edge 1270 presses against seal 1216 to providea seal between sealing edges 1268 and 1270 of main body 1210 and cover1212.

According to an alternative embodiment of the present disclosure, thesealing edges disclosed herein that press against the O-ring, such assealing edge 1270, are provided with a ridge that “bites” into theO-ring, such as O-ring 1216, along the length of the O-ring to increasethe compression of the O-ring and the contact pressure between thesealing surface and the O-ring. According to an alternative embodimentof the present disclosure, sealing edges and an O-ring are providedaround the opening in main body 1210 that receives third link 1122 oflinkages 1114 to seal around this opening. Similar sealing edges andO-ring may also provided for foot end rail 22. According to anotherembodiment, these additional sealing edges extend down to the existingsealing edges.

Shells 1246, 1248 of housing 1236 of second controller 54 are sealedtogether to prevent fluids from entering interior region 1250 definedbetween shells 1246, 1248 as shown in FIG. 61. Similar to main body 1210and cover 1212 of head end siderail 20, shells 1246, 1248 includesealing edges 1336, 1338 that face each other when shells 1246, 1248 arecoupled together. Similar to sealing edge 1268 of main body 1210,sealing edge 1338 of shell 1248 includes a channel 1340 extending fromone side of post 1252, around the perimeter of shell 1248, to theopposite side of post 1252. An O-ring seal 1342 made of rubber or othersuitable material is positioned in channel 1340. When shell 1246 ispositioned on shell 1248, sealing edge 1336 presses against seal 1342 toprovide a seal between sealing edges 1336 and 1338 of shells 1246 and1248, respectively.

Similar to rail member 1110 of head end siderail 20, rail member 1112 offoot end siderail 22 includes a main body 1211 and a cover 1213 as shownin FIG. 65. An O-ring seal 1217 is provided between main body 1211 andcover 1213 to prevent liquids from an interior region 1219 definedbetween main body 1211 and cover 1213 as shown in FIGS. 66 and 67. Mainbody 1211 and cover 1213 include sealing edges 1269, 1271 that face eachother when cover 1213 is coupled to main body 1211.

Sealing edge 1269 includes a channel 1333 as shown in FIGS. 66 and 67.O-ring seal 1217, made of rubber or other suitable material, ispositioned in channel 1333. When cover 1213 is positioned on main body1211 of foot end siderail 22, sealing edge 1271 presses against seal1217 to provide a seal between sealing edges 1269, 1271 of main body1211 and cover 1213.

Detachable Siderail Controller

As shown in FIG. 45 control system 44 is further coupled to detachablesiderail controller 50 that may be a corded pendant configured toremovably and slidably couple to head and foot end siderails 20, 22. Asshown in FIG. 68 controller 50 includes a housing 1344, a circuit board1346 including a plurality of control buttons or switches 1348, and acord 1350 coupled to circuit board 1346 and extending from housing 1344as shown in FIG. 69 The functions controlled by switches 1348 will bedescribed in greater detail below.

Controller 50 is configured to slide in either handle opening 1292 ofhead end siderails 20 or handle opening 1352 of foot end siderails 22between an infinite number of positions (FIG. 45). Because patients varyin size, one patient may find it more convenient to position controller50 in one of the many available positions on either head or foot endsiderails 20, 22 than another patient. Thus, various patients canposition controller 50 in any of the infinite number of positions on anyof head or foot end siderails 20, 22 depending on the preference ofparticular patient positioned on patient support 10. Furthermore, apatient may decide to adjust the position of controller 50 if theconfiguration of deck 26 is changed. For example, if head section 38 ofdeck 26 is raised, a patient may desire to reposition controller 50along the particular siderail 20, 22 or remove controller 50 and placeit on another siderail 20, 22.

As shown in FIGS. 45 and 68, housing 1344 of controller 50 includes anupper or first concave surface 1354 and a lower or second concavesurface 1356 that complement convex surfaces 1358 and 1360,respectively, of rail member 1110 of head end siderail 20. Also as shownin FIG. 45, rail member 1112 of foot end siderail 22 includes convexsurfaces 1362 and 1364 that are complemented by concave surfaces 1354and 1356, respectively. As shown in FIG. 68, a substantial portion ofcontroller 50 is positioned within rail member 1110 so that controller50 maintains a relatively low profile compared to an inner surface 1366of rail member 1110 when positioned in rail member 1110 to avoidinterference with other components of patient support 10 or other piecesof medical equipment. According to alternative embodiments of thepresent disclosure, the controller 50 is positioned further in theopening formed in the rail member 1110, so that little or none of thecontroller extends beyond an inner surface of the rail member.

The respective pairs of convex surfaces 1358, 1360, 1362, 1364 ofsiderails 20, 22 cooperate to define a top rail and a bottom rail thatdefine a guide 1367 operably coupled to the controller 50. Concavesurfaces 1354 and 1356 and a retainer 1368 coupled to housing 1344cooperate to define a complementary formation configured to ride alongthe top and bottom rails/guide. According to alternative embodiments ofthe present disclosure, other configurations of rails and guides andcomplementary formations are provided such as raised rails, channels,slots, or other configurations of guides and complementary formationsknown to those of ordinary skill in the art.

Retainer 1368 is configured to retain controller 50 in either opening1292, 1352 to permit sliding of controller 50 along siderails 20, 22 andto permit removal of controller 50 from openings 1292, 1352,respectively. When controller 50 is positioned in opening 1352 of footend siderail 22, retainer 1368 is positioned adjacent to concave surface1356 of housing 1344.

As illustrated in FIG. 68, retainer 1368 includes a spring-biasedretainer or latch member 1370. When a patient pulls on controller 50 indirection 1374, retainer member 1370 is pushed inwardly in direction1375 so that a curved distal end 1376 of retainer member 1370 rides overthe inner most portion of convex surface 1360, 1364. As such, retainer1368 no longer retains controller 50 in the respective siderail 20, 22.

To reposition controller 50 back in one of siderails 20, 22, the patientpositions second concave surface 1354 adjacent to convex surface 1358,1362 of rail member 1110, 1112 of siderail 20, 22, respectively so thata peaked tip 1378 of housing 1344 captures rail member 1110, 1112. Thelower end of controller 50 is pushed in direction 1380 so that retainermember 1370 rides back over respective convex surface 1360, 1364. Peakedtip 1378 and retainer member 1370 then define a width 1382 that isgreater than a width 1384 of opening 1292, 1352 so that controller 50 isretained in respective siderail 20, 22. Identical procedures arefollowed for placing and removing controller 50 from opening 1352 infoot end siderails 22 and for placing and removing controller 50 fromopening 1292 in head end siderails 20. Furthermore, controller 50 mayalso be coupled to rail members 1110, 1112 through the opposite side ofrespective opening 1292, 1352. According to an alternative embodiment ofthe present disclosure, the openings in the head and foot end siderailsdo not extend completely through the siderails.

As shown in FIG. 68, housing 1344 includes inner and outer shells 1386and 1388 that cooperate to define an interior region 1390 configured toreceive circuit board 1346. Outer shell 1388 defines aretainer-receiving void 1394 sized to receive portions of retainer 1368.Housing 1344 further includes a retainer cover 1396 that cooperates withouter shell 1388 to define void 1394. Retainer 1368 further includes abiasing member or spring 1398 positioned in void 1394 between outershell 1388 and retainer member 1370. Spring 1398 biases retainer member1370 in direction 1410 toward convex surface 1360 as shown in FIG. 68.According to alternative embodiments of the present disclosure, otherbiasing members are provided, such as torsion springs, the retainermember being cantilevered and flexible, or other configurations ofbiasing members known to those of ordinary skill in the art.

As shown in FIGS. 69 and 70, retainer member 1370 includes a latchportion 1412, a pair of ribs 1414, a pair of locking tabs 1416, and anotched rib 1418. Latch portion 1412 includes a downwardly facingsurface 1420 that matches the contour of upwardly facing surface 1360,1364 of siderails 20, 22, respectively as shown in FIGS. 45 and 68.Latch portion 1412 further includes a spring-receiving aperture 1422sized to receive an end of spring 1398.

Ribs 1414 slide in channel portions 1424 of void 1394 so that retainermember 1370 can move up and down. Housing 1344 includes a pair of lips1426 on which locking tabs 1416 are caught preventing removal ofretainer member 1370 from void 1394 after retainer member 1370 isslidably moved up and locking tabs 1416 snap into place over lips 1426.

Retainer 1368 further includes a lock or blocker 1430 configured toslide on retainer cover 1396 and block or permit movement of retainermember 1370. As shown in FIGS. 68-70, lock 1430 includes a slider button1432 and a blocker or lug 1434 coupled to button 1432 by a screw 1436 sothat retainer cover 1396 is positioned between lug 1434 and button 1432.Retainer cover 1396 with slider button 1432 and blocker 1434 coupledthereto, is coupled to housing 1344 so that blocker 1434 is positionedabove notched rib 1418 as shown in FIG. 68. A portion of slider button1432 passes through a lock guide or opening 1428 configured to guidelock 1430 in movement.

Depending on the position of button 1432 and blocker 1434 relative tolock guide 1428, blocker 1434 will prevent or permit movement ofretainer member 1370 relative to housing 1344. If button 1432 iscentered over a middle or lower portion 1438 of notched rib 1418,clearance exists between lower portion 1438 and blocker 1434 andretainer member 1370 is permitted to move further up in direction 1375into void 1394 (FIG. 68). As mentioned above, this movement permitsremoval of controller 50 from respective head and foot end siderails 20,22. However, if button 1432 is slidably moved so that blocker 1434 ispositioned over a raised portion 1440 of notched rib 1418, there islittle or no clearance between raised portion 1440 and blocker 1434 andretainer member 1370 is blocked from sliding further up in direction1375 into void 1394 (FIG. 68). Cover 1396 includes a pair of ridges 1395that restrain a ridge 1397 on button 1432 to resist movement of button1432 between the locked position and the unlocked position.

An alternative embodiment retainer 1442 and retainer cover 1444 similarto retainer 1368 and retainer cover 1396 are shown in FIG. 71. Retainercover 1444 cooperates with outer shell 1388 to define a void sized toreceive portions of retainer 1442. Retainer 1442 includes a retainermember 1446 and spring 1398 positioned in the void between outer shell1388 and retainer member 1446. Spring 1398 biases retainer member 1446in direction 1448 toward convex surface 1360, 1364 of respectivesiderail 20, 22.

Retainer member 1446 includes a latch portion 1450, a pair of ribs 1452,a pair of locking tabs 1454, and a notched rib 1456. Latch portion 1450includes a downwardly facing surface 1458 that matches the contour ofupwardly facing surface 1360, 1364 of siderails 20, 22, respectively.Latch portion 1450 further includes a spring-receiving aperture 1460sized to receive an end of spring 1398.

Ribs 1452 slide in channel portions 1424 of void 1394 so that retainermember 1446 can move up and down. Locking tabs 1454 are caught on lips1426 of housing 1344 to prevent removal of retainer member 1446 fromvoid 1394 after retainer member 1446 is slidably moved up and lockingtabs 1454 snap into place over lips 1426.

Retainer 1442 further includes a lock or blocker 1464 configured toslide on retainer cover 1444 and block or permit movement of retainermember 1446. Lock 1464 includes slider button 1432 and a blocker or lug1466 coupled integrally with button 1432. Lock 1464 includes a pluralityof fingers 1468 that snap into an opening 1470 in cover 1444 so that lug1466 extends through opening 1470. Cover 1444 with lock 1464 coupledthereto, is coupled to housing 1344 so that blocker 1466 is positionedabove notched rib 1456.

Depending on the position of button 1432 and blocker 1466 relative tocover 1444, blocker 1466 will prevent or permit movement of retainermember 1446 relative to housing 1344. If button 1432 is centered over amiddle or lower portion 1472 of notched rib 1456, clearance existsbetween lower portion 1438 and blocker 1466 and retainer member 1446 ispermitted to move further up into void 1394. This movement permitsremoval of the controller 50 from respective head and foot end siderails20, 22. However, if button 1432 is slidably moved so that blocker 1466is positioned over a raised portion 1474 of notched rib 1456, there islittle or no clearance between raised portion 1474 and blocker 1466 andretainer member 1446 is blocked from sliding further up into the void.

According to other alternative embodiments of the disclosure, otherretainers known to those of ordinary skill in the art are provided toretain the controller in the siderails such as tabs, clasps, catches,locks, other latches, clamps, pins, bolts, bars, hasp, hooks, or otherretainers known to those of ordinary skill in the art.

As shown in FIG. 72, cord 1350 communicates electric signals to and fromcontroller 50. Cord 1350 includes a connector (not shown) that couplesto either of two connectors 1478 shown in FIG. 45 on weigh frame 36.According to the illustrative embodiment of the disclosure, one ofconnectors 1478 is coupled to a first side of patient support 10 and theother connector 1478 is coupled to an opposite second side of patientsupport 10. A plurality of wires (not shown) are coupled to eachconnector 1478, and are configured to communicate with the variouselectrically controlled devices of patient support 10.

Because two connectors 1478 are provided on opposite sides of patientsupport 10, controller 50 may be plugged into either side of patientsupport 10. Thus, if a patient or caregiver finds it more convenient toposition controller 50 on the pair of head and foot end siderails 20, 22on the first side of patient support 10, controller 50 can be pluggedinto connector 1478 without cord 1350 having to be strung over themattress 14. Similarly, if a patient or caregiver finds it moreconvenient to position controller 50 on the pair of head and foot endsiderails 20, 22 on the second side of patient support 10, controller 50can be plugged into connector without cord 1350 having to be strung overthe mattress 14. Thus, a corded controller 50 is provided that can beremovably coupled to either side of the patient support 10 withouthaving to string the cord 1350 of the controller 50 over the mattress 14of the patient support 10.

Controller 50 further includes a rubber grommet 1480 that is positionedin a aperture 1482 in outer shell 1386 as shown in FIGS. 69 and 72. Cord1350 extends through grommet 1480. Grommet 1480 provide a water-tightseal between shell 1388 and cord 1350.

Outer shell 1388 further includes a pair of symmetric ribs or ramps 1482that define a tapered channel 1484 configured to receive cord 1350. Astop 1486 is coupled to cord 1350. Stop 1486 is larger than a narrowopening 1488 defined between ramps 1482 so that cord 1350 cannot bepulled axially out of outer shell 1386. This prevents wires 1490 of cord1350 and connector 1492 that couples to circuit board 1346 from beingstressed if force is applied to cord 1350. Because channel 1484 istapered, an assembler can initially place cord 1350 in the wider portionof channel 1484 and then press down to position cord 1350 in opening1488. When cord 1350 is pressed down on, ramps 1482 guide cord 1350toward narrow opening 1488 so that the assembler does not have to be asaccurate with the initial placement of cord 1350 in channel 1484.According to the presently preferred embodiment, the stop 1486 is acable tie that has had any extra length removed. According toalternative embodiments of the present disclosure, other stops areprovided. For example, according to one alternative embodiment, a stapleor other clip is provided.

As shown in FIG. 68, inner and outer shells 1386, 1388 includesperimeter channels 1494, 1496. During the manufacture of inner shell1394, a seal 1498 is formed in channel 1494. Preferably, shells 1386,1388 are made of rigid plastic materials and seal 1498 is made of arubber-like material that forms a liquid-proof seal between outer shells1386, 1388.

Controller Interface Panels Controllers 50, 52, 54 each includerespective interface panels 1510, 1512, 1514, illustrated in FIGS.73-75. Preferably, each panel 1510, 1512, 1514 is made of a flexiblemembrane. Panel 1510 couples to inner shell 1386 of controller 50 toprovide a liquid-proof seal therebetween. Similarly, panel 1512 couplesto cover 1212 of head end siderail 20 to provide a water-proof sealtherebetween, and panel 1512 couples to outer housing 1248 of controller54 to provide a water-proof seal therebetween.

Each interface panel 1510, 1512, 1514 includes a plurality statusindicators and raised button covers having indicia. When a user presseson the button covers, they also press on one of respective switches orbuttons 1348, 1232, 1240 positioned behind the button cover and initiatea function of patient support 10.

As shown in FIG. 73 interface panel 1510 includes a plurality ofmembrane input control buttons or raised button covers 1516 and aplurality of status indicators 1518 which are electrically coupled tocircuit board 1346 of controller 50, allowing controller 50 to be usedby persons in or out of patient support 10 to control the operation ofvarious features of patient support 10, including articulation of deck26, sending a nurse call signal, controlling entertainment devices, suchas television, radio, or the like. In a preferred embodiment, statusindicators 1518 are light emitting diodes (LEDs) electrically coupled tocircuit board 1346. According to alternative embodiments of the presentdisclosure, other functions of the patient support 10 or remoteequipment are controlled by the controller 50.

Head up button 1520 and head down button 1522 are provided to controladjustment of the position of head section 38 of deck 26 between theraised and lowered positions. Knee up button 1524 and knee down button1526 are provided to control adjustment of the position of leg and seatsections 42 and 40.

When a nurse call button 1528 is pressed, a signal is sent to a nursestation or directly to predetermined caregivers that indicates that thepatient needs attention. Speak indicator 1529 and listen indicator 1530are provided to indicate the direction of communication between apatient in patient support 10 and nurse or other caregiver located at anurse call station or other location. The caregiver at the nurse callstation or elsewhere controls which way the communication travels. Ifneither indicator 1529, 1530 is illuminated, the communication lines areclosed. When speak indicator 1529 is illuminated, the patient may speakto the caregiver. The patient speaks into a microphone (not shown)coupled to head end siderail 20. When listen indicator 1530 isilluminated, the caregiver may speak to the patient in patient support10 from speakers 1220. A graphic of a listening ear is positionedadjacent to speak indicator 1529 to indicate that a nurse or othercaregiver is listening to the patient when lit. A graphic of a speakingperson is positioned adjacent to listen indicator 1530 to indicate thepatient is to listen to a nurse or other caregiver when illuminated.

Controller 50 is also configured to control functions of other deviceslocated within a patient's room such as a TV or lighting of a room (notshown) as further described above with reference to FIG. 35. TV button1532 controls turning on and off a TV (not shown) located in a room.When TV button 1532 is pressed, the TV is turned on. When TV button 1532is pressed again, the TV is turned off. To change the channel of the TV,channel up and channel down buttons 1534, 1536 are pressed. To changethe TV volume up or down, volume up and volume down buttons 1538, 1540are pressed. To turn closed captioning of the TV on and off, a closedcaption button 1542 is pressed. Radio button 1544 controls turning onand off a radio (not shown) broadcasting from speakers 1220 or elsewherein the patient's room. When only the radio is on, channel up and downbuttons 1534, 1536 and volume up and down buttons 1538, 1540 operate thechannels and volume of the radio. If both the radio and TV are on,channel up and down buttons 1534, 1536 and volume up and down buttons1538, 1540 operate the TV only.

To turn on the direct lighting in a room, such a ceiling light or otherlighting that shines down, a direct light button 1546 is provided thatis pressed to turn the light(s) on and off. Similarly, to turn onindirect lightly, such as a light on a headwall unit that shines up onthe ceiling or down on the floor from a low level, an indirect lightbutton 1548 is provided that is pressed to turn the light(s) on and off.

As shown in FIG. 74 interface panel 1512 includes a plurality ofmembrane input control buttons or raised button covers 1516 and aplurality of status indicators 1518 which are electrically coupled tocircuit board 1233 of controller 52, allowing controller 52 to be usedby persons out of patient support 10 to control the operation of variousfeatures of patient support 10, including extension, tilting, andarticulation of deck 26, sending a nurse call signal, and enablement ofthe other functions of patient support 10. In a preferred embodiment,status indicators 1518 are LED's electrically coupled to circuit board1233. According to alternative embodiments of the present disclosure,other functions of the patient support or remote equipment arecontrolled by the controller.

Head up button 1550 and head down button 1551 are provided to controladjustment of the position of head section 38 of deck 26 between theraised and lowered positions. Knee up button 1552 and knee down button1554 are provided to control adjustment of the position of leg and seatsections 42 and 40. High button 1556 and low button 1558 are provided tocontrol raising and lowering intermediate frame 32 relative to baseframe 28.

Foot extend button 1560 and foot retract button 1562 cause leg section42 to extend and retract which permits the position of footboard 18 ofpatient support 10 to be adjusted relative to the position of thepatient's foot. To extend leg section 42, extend button 1560 is presseduntil the desired position of footboard 18 is reached. To retract footsection 42, retract button 1562 is pressed until the desired position isreached.

Chair bed button 1564 and flat bed button 1566 are provided to controladjustment of the position of deck 26 between the chair and bedpositions. To move patient support 10 toward the chair position, chairbutton 1564 is pressed until the degree of the chair position isachieved of until patient support 10 reaches the full chair position. Tomove patient support 10 toward the bed position, flat bed button 1566 ispressed until the desired degree of the chair position is removed oruntil patient support 10 reaches the flat bed position.

Tilt (Reverse Trendelenburg) button 1568 and reverse tilt(Trendelenburg) button 1570 are provided to control adjustment of theposition of deck 26 between head raised (Reverse Trendelenburg) and headlowered (Trendelenburg) positions. To move patient support 10 to thehead raised position, tilt button 1568 is pressed until the degree ofthe incline of intermediate frame 32 is achieved. To move patientsupport 10 toward the head lowered position, reverse tilt button 1570 ispressed until the desired degree of incline of intermediate frame 32 isachieved. When a nurse call button 1572 is pressed, a signal is sent toa nurse station or directly to predetermined caregivers that indicatesthat the patient needs attention.

According to the illustrative embodiment of the present disclosure, mostof the buttons are only operable after a key or enable button 1584 isfirst pressed. This helps prevent the accidental activation anddeactivation of certain functions of patient support 10. According tothe preferred embodiment of the present disclosure, enable button 1584must first be pressed before the functions controlled by the otherbuttons on panels 1512 and 1514 will initiate. However, the nurse callfeature controlled by nurse call button 1572 will initiate without theneed to first press enable button 1584.

To enable the other buttons, enable button 1584 must be pressed for atleast or about 0.5 seconds. By requiring that the button be depressedfor a predetermined amount of time, an accidental momentary depressionof enable button 1584, such as when panel 1512 is wiped during cleaning,will not enable the other buttons.

Once enabled, the user has about a twenty second window to press theother buttons to initiate a function. Once the twenty second windowpasses without one of the other buttons being pressed, the other buttonsare disabled and enable button 1584 must be pressed again to operate thefunctions. However, if one of the other buttons is pressed during theinitial twenty second window, the window is reset so that the user hasanother twenty second window to press another button. Once twentyseconds passes without any button being pressed, the twenty secondwindow expires and enable button 1584 must be pressed again.

According to alternative embodiments of the present disclosure, othertimes required to press the enable button are provided. For example,according to one embodiment, one second is required. According toanother embodiment, no time is required so that the other buttons areenabled whenever the enable button is pressed. According to otheralternative embodiments of the present disclosure, other windows of timeare provided during which the other buttons are enabled. For example,according to some embodiments, the window is 5, 10, 15, 25, 30 or moreseconds. According to another alternative embodiment, no enable button1584 is provided.

Patient control 52 also enables and disables (locks out) specificfeatures of patient support 10. By pressing head lock-out button 1586,the function of head up buttons 1520, 1551 and head down buttons 1522,1550 of respective controllers 50, 52 are disabled so that head section38 of deck 26 cannot be raised or lowered. When disabled, an indicator1588 on button 1586 lights up. When head lock-out button 1586 is pressedagain, head section 38 may be raised and lowered again and indicator1588 goes off. A similar knee lock-out button 1590 and indicator 1592are provided to enable and disable the function of knee up buttons 1524,1552 and knee down buttons 1526, 1554 of respective controllers 50, 52.

A similar all actuator lock-out button 1594 and indicator 1596 areprovided that disable the function or initiate movement of linearactuators 48 operated by controllers 50, 52. When pressed, all functionscontrolled by controllers 50, 52 that change the configuration of deck26 or raise, lower, or tilt intermediate frame 32 are disabled andindicator 1596 lights up. When pressed again, the functions are enabledand indicator 1596 turns off. By disabling certain functions ofcontrollers 50, 52, a caregiver can prevent accidentally articulation orother movement of patient support 10 when such articulation may beundesirable. According to alternative embodiments of the presentdisclosure, the other functions of controllers 50, 52, 54 are alsodisabled and enabled by one or more lock-out buttons.

Other indicators which relate to various patient support statusfunctions are also included on interface panel 1512. A bed positionindicator 1598 is illuminated when intermediate frame 32 is not in thelowermost position. When intermediate frame 32 is in the lowermostposition, this indicator 1598 is off. A service indicator 1610 is litwhen patient support 10 detects that a component needs serviced. Ifpatient support 10 does not detect that a component needs serviced, thisindicator 1610 is off.

With reference to FIG. 75, interface panel 1514 includes a plurality ofmembrane input control buttons or raised button covers 1516 and aplurality of status indicators 1518 which are electrically coupled tocircuit board 1238 of controller 54, allowing controller 54 to be usedby persons out of patient support 10 to control the operation of variousfeatures of patient support 10, including detecting the position of apatient, the patient's weight, and operation of mattress 14. In apreferred embodiment, status indicators 1518 are LED's electricallycoupled to circuit board 1238. According to alternative embodiments ofthe present disclosure, other functions of the patient support or remoteequipment are controlled by the controller.

As shown in FIG. 75, patient position monitor buttons 1612, 1614, 1616are provided to control activation of a patient position monitoringsystem, which notifies a caregiver when the patient changes positionrelative to patient support 10. When one of buttons 1612, 1614, 1616 isselected, the other respective buttons 1612, 1614, 1616 areautomatically deselected. Status indicators 1518 are provided with eachbutton 1612, 1614, 1616 indicating which of the monitoring modes is on.Patient position sensors 5004, 5008, 5010 are positioned on deck 26underneath mattress 14. Details of suitable patient position detectionsystems are provided in U.S. Pat. No. 6,208,250, to Dixon et al.; U.S.Pat. No. 6,067,019, to Scott; and U.S. Pat. No. 5,808,552, to Wiley etal., the disclosures of which are expressly incorporated by referenceherein.

Button 1616 controls activation of the position monitoring system todetect an “exit” condition when the patient has exited patient support10. When button 1616 is pressed to activate monitoring of the exitcondition, the respective indicator 1518 on button 1616 lights up.Otherwise the respective indicator 1518 on button 1616 is off. If theexit condition is detected by bed exit sensor 562, visual and audiblealarms will activate notifying the caregiver that the patient has exitedpatient support 10.

Button 1614 controls activation of the position monitoring system todetect a “pre-exit” condition when the patient is bearing weightprimarily on an edge of patient support 10, such as when the patient issitting on the edge of patient support 10. When button 1614 is pressedto activate monitoring of the pre-exit condition, the respectiveindicator 1518 on button 1614 lights up. Otherwise the respectiveindicator 1518 on button 1614 is off. If the pre-exit condition isdetected, the visual and audible alarms will activate notifying thecaregiver that the patient has moved to the edge of patient support 10.Furthermore, the alarms will also activate if the exit condition isdetected.

Button 1612 controls activation of the position monitoring system todetect a “patient up” condition when the patient's torso moves beyond apredetermined position relative to deck 26. When button 1612 is pressedto activate monitoring of the patient up condition, the respectiveindicator 1518 on button 1612 lights up. Otherwise the respectiveindicator 1518 on button 1612 is off. If the patient up condition isdetected, the visual and audible alarms will activate notifying thecaregiver that the patient has moved to the up position.

Alarm control button 1618 and volume indicator 1620 are provided to acaregiver to control the volume of the audible alarm that sounds whenthe patient monitoring system detects one of the above-mentionedconditions. Alarm button 1618 controls the volume of the alarm. Volumeindicator 1620 comprises a plurality of LED's that are lit according tothe selected volume level, i.e., the higher the volume selected, themore LED's that are lit. If a user wants to turn the volume up, alarmbutton 1618 is pressed repeatedly until the desired volume is reached.To lower the volume, alarm button 1618 is pressed repeatedly until thepeak volume is reached. After the peak volume is reached, continuedpressing on alarm button 1618 will gradually reduce the volume of thealarm until the lowest volume is reached. After the lowest volume isreached, continued pressing on alarm button 1618 will gradually increasethe volume. If no LED's are lit, the alarm is deactivated.

Inflation system buttons 1622, 1624, 1626, 1628 are provided thatcontrol the function of the air pressure inflation system of mattress14. Maximum inflation button 1622 inflates the mattress zones to apredefined air pressure level and may be used to facilitateadministration of CPR. A corresponding indicator 1518 on button 1622lights up when the maximum inflation function is activated. When pressedagain, the mattress zones return to normal operating pressure and thecorresponding indicator 1518 turns off.

First turn assist button 1624 controls the turning of a patient towardone side of patient support 10. Second turn assist button 1626 controlsthe turning of the patient toward the other side of patient support 10.When either of these buttons 1624, 1626 are pressed, they begin the turnassist function and the associated indicator 1518 lights up. When therespective turn assist function is complete, the associated indicators1518 turn off. A rail down indicator 1627 is illuminated when any ofsiderails 20, 22 are not in the raised position. Patient size button1628 button permits a caregiver to set the size of the patientpositioned on mattress 14. Three graphics representing different sizedpatients are positioned next to corresponding indicators 1518. Whenpatient size button 1628 is pressed, a different sized patient isselected and the corresponding indicator 1518 lights up. In anillustrative embodiment, depending on which size patient is selected,different air pressures are provided to mattress 14.

Interface panel 1514 further includes a plurality of buttons and LEDdisplay 1242 which permit a caregiver to weigh the patient using thepatient weighing function. A unit selection button 1630 enables thecaregiver to choose between pounds and kilograms as the unit of weightmeasurement. LED display 1242 displays the patient's weight and selectedunit of measurement.

Calibration button 1632, change item button 1634, add item button 1636,and subtract item button 1638 are provided to the caregiver to calibratethe system for weighing a patient. For example, before a patient isplaced on patient support 10, calibration button 1632 is pressed to setthe weight reading to 000.0 lbs/kg so that the initial weight ofmattress 14, deck 26, and any other patient support component or pieceof medical equipment is negated from the weight reading. Thus, only theweight of the patient is indicated when the patient is on patientsupport 10.

If a patient support component or piece of medical equipment is added toor removed from patient support 10 that may affect the weight reading,change item button 1634, add item button 1636, and subtract item button1638 are illustratively used to take the additional or subtracted weightinto account. For example, if a piece of medical equipment, such as anIV pole, is added to patient support 10, change item button 1634 and additem button 1636 are pressed while the piece of medical equipment isadded and the additional weight detected by the weigh system issubtracted from the measured weight so that the additional weight of theIV pole is negated from the weight displayed on display 1242. Similarly,if a piece of medical equipment is removed from patient support 10,change item button 1634 and subtract item button 1638 are pressed whilethe piece of medical equipment is removed and the removed weightdetected by the weigh system is added to the measured weight so that theloss of weight of the removed pieced of medical equipment is negatedfrom the weight displayed on display 1242.

Foot Pedal Controls and Nightlight

As shown in FIG. 1, foot pedal controls 56 are coupled to base frame 28.Foot pedal controls 56 are provided to control raising and lowering ofdeck 26 relative to base frame 28 and to control raising and loweringhead section 38 of deck 26 relative to weigh frame 36.

Each foot pedal control 56 is associated with one of the above-mentionedfunctions and includes a pedal or control member 1660 appropriatelylabeled for the respective function. By stepping on any of pedals 1660with the tip of one's foot as shown in FIG. 76, one of these functionsof patient support 10 is activated. When pedals 1660 are released, theyare automatically biased back to the neutral position and the functionterminates.

With reference to FIGS. 76-79, pedals 1660 are pivotably coupled to apedal housing 1662 that is fixedly coupled to base frame 28 in aspaced-apart relationship with the floor 29. Pedal housing 1662 includesan L-shaped body portion 1664 that couples to base frame 28 and ahousing portion 1666 that defines an enclosed space 1668.

Because housing portion 1666 is centrally located and raised relative tofoot pedals 1660, it acts as a locator for pedals 1660. For example, acaregiver who is familiar with patient support 10 will be able to sweeptheir foot over pedals 1660 until striking either side of housingportion 1666. Because of their familiarity with patient support 10, theywill recognize which pedal 1660 is located beneath their foot. If thispedal 1660 performs the desired function, the need only step downwithout looking down at the respective pedal 1660 for an decal orindicator that indicates the specific function of that respective pedal1660. If the desired pedal 1660 is not the one located under their foot,they will recognize that they need to back away from housing portion1666 to the next adjacent foot pedal 1660 that does perform the desiredfunction. Preferably, the caregiver will initially sweep toward thecorrect side of housing portion 1666 on which the desired foot pedal1660 is located.

As shown in FIGS. 77 and 78, each pedal 1660 is pivotable between afirst or up position and a second or down position. Each pedal 1660 hasa stepped profile and includes a pedal portion 1670, a pivot portion1672, and a sensor portion 1674. Pedal portion 1670 extends beyond pedalhousing 1662 to permit a caregiver to press down on pedal portion 1670as shown in FIG. 76. When in the first raised position, a top surface1676 of pedal portion 1670 is about 6 inches above the floor 29 so that5.5 inches of clearance 1677 exists under pedal portion 1670.Furthermore, this spacing permits a caregiver or other person to operatepedals 1660 while his or her heal 1680 rests on floor 29. Because thecaregiver's heal 1680 is on the ground 29 during the movement of patientsupport 10, his or her foot is further away from the moving componentsof the patient support. Preferably, decals or indicators (not shown) areprovided on inward portions 1682 of top surface 1676 that is at an angleof 45 degrees from horizontal to help a caregiver's line of sight inviewing the decal or indicator that indicates what function of patientsupport 10 is controlled by the particular pedal 1660.

As shown in FIG. 79, a pin 1684 is provided that extends through pivotflanges 1686 and to define a pivot axis 1688 about which pedals 1660pivot on housing 1662. Each foot pedal control 1660 includes a biaser orspring 1690 through which pin 1684 extends that biases pedal 1660 uptoward the first raised position.

The position of each pedal 1660 is detected by a sensor 538. If sensor538 detects that any one of pedals 1660 is moved and held in the secondlowered position for about one second and then returned to the firstraised position, pedals 1660 are enabled to operate the respectivefunctions of patient support 10 for twenty seconds. To activate any ofthese functions, a respective pedal 1660 must be moved to the secondlowered position within the twenty second enabled window.

If a pedal 1660 is not moved back down to the second lowered positionwithin the twenty second enabled widow, pedals 1660 are disabled andmust be enabled again as described above by holding one of pedals 1660in the second lowered position for about one second. If any of pedals1660 are lowered within the twenty second window, the function isperformed and the window is reset for another twenty seconds. If twentyseconds go by without any of the pedals 1660 being moved back down tothe second lowered position, pedals 1660 are again disabled. If twopedals 1660 are simultaneously moved to the second lowered position,neither function is performed. Preferably, pedals 1660 travel through anangle of 50 degrees from the first raised position to the second loweredposition.

Each of the four sensors 538 is preferably mounted to one of a pair ofmounting strips 1694 as shown in FIGS. 79 and 80 (only one is shown inFIG. 79) mounted to housing 1662. A cable 1696 is coupled to each sensor538 (only one is shown in FIG. 79) to send signals indicative of theposition of pedal 1660 detected by sensor 538. Cables 1696 extend intoenclosed space 1668. Each cable 1696 is coupled to a circuit board 1698positioned in enclosed space 1668 and a single cable is coupled tocontrol system 44 to control respective linear actuators 48. A cover1699 is also provided that encloses interior space 1668.

According to the preferred embodiment of the present disclosure, sensor538 is a Hall effect field sensor that detects change in thecharacteristics of a magnetic field generated by pedal 1660. A magnet1710 is positioned on sensor portion 1674 of each pedal 1660 in aposition spaced apart from sensor 538. Sensor 538 detects the change inposition of magnet 1710 during movement of the respective pedal 1660 bydetecting the change in magnetic field. Based on this change in magneticfield, sensor 538 sends a signal indicative of the first raised andsecond lowered positions of the respective pedal 1660 to the controlsystem 44. Control system 44 then initiates the application of power toactuators 48 to control and power the function of the respectivecomponents of patient support 10.

An illustrative circuitry associated with sensor 538 is shown in FIG.81. The circuitry includes an op-amp 1714 coupled to sensor 538, an opencollector 1716, a transistor 1718, and a resistor 1720. Sensor 538,op-amp 1714, open collector 1716, and transistor 1718 are coupled toground 1722. Sensor 538, op-amp 1714, open collector 1716, and resistor1720 are coupled to a 5 volt source. Transistor 1718 and resistor 1720are coupled to the output of the circuit. Illustratively, resistor 1720is 470 ohms and sensor 538 is a Cherry MP1013 snap fit proximity sensorsold by The Cherry Corporation, 3600 Sunset Avenue, Waukegan, Ill. thatdetects magnetic fields.

As shown in FIG. 80, four pedals 1660 are provided to control variousfunctions of patient support 10 when pushed down. For example, a firstpedal 1724 is provided that when pivoted down, raises head section 38 ofdeck 26. A second pedal 1726 is provided for lowering head section 38relative to weigh frame 36 when pivoted down. Series of pedals 1660 alsoincludes a third pedal 1728 for raising intermediate frame 32 relativeto base frame 28 when pivoted down, and a fourth pedal 1730 is providedfor lowering intermediate frame 32 when pivoted down. According to analternative embodiment, the plurality of pedals 1660 also includes apedal for extending and retracting leg section 42 of the patient support10 or for activating any other feature of the patient support 10.

As shown in FIGS. 79 and 80, a light 1732 is provided on cover 1699.Light 1732 illustratively includes four LED's (not shown) and is coupledto circuit board 1698. Preferably, light 1732 shines on floor 1678 sothat a silhouette of pedals 1660 is provided in a semi-dark or darkroom. Therefore, enough light is provided that a caregiver can locatefoot pedals 1660 without producing enough light that would disturb aresting patient.

An alternative embodiment foot pedal control 56′ is illustrated in FIG.82. Foot pedal control 56′ is substantially similar to foot pedalcontrol 56, such that like reference numbers are used to identify likecomponents.

As shown in FIGS. 57 and 82, foot control pedal 56′ includes light 1732′which is provided on pedal housing 1662′. Light 1732′ includes fourLED's (not shown) and is coupled to circuit board 1698. According to theillustrative embodiment of FIG. 57, light 1732′ is positioned at the endof pedal housing 1662′ positioned nearest the longitudinal center ofpatient support 10′.

According to alternative embodiments of the present disclosure, light1732 is placed elsewhere on the patient support 10 to shine directly onfoot pedals 1660. For example, according to one alternative embodiment,light 1732 is provided on the sides of housing portion 1666 (see FIGS. 1and 58) of pedal housing 1662 so that light 1732 shines directly onpedals 1660. According to another alternative embodiment, a light 1732is provided above pedals 1660. For example, according to one embodiment,light 1732 is mounted on the outwardly facing surface of the bodyportion 1664 of pedal housing 1662. In other alternative embodiments,light 1732 is mounted on the bed frame or other components of patientsupport 10, such as siderails 20, 22 or deck 26, to shine directly downon pedals 1660. As shown in FIG. 8, a set of foot pedal controls 56 aresupported on base frame 28 on the opposite side of patient support 10.Pedal controls 56 on opposite sides of patient support 10 are mirrorimages of each other.

According to alternative embodiments of the present disclosure, othersensors are provided to detect the position of the pedals 1660 and tocontrol the respective functions of the patient support 10, such asother proximity switches, a three-position mechanical switch, othermechanical switches, other electrical switches, other field sensors thatdetect changes in an electric field due to changes in capacitance orinductance, other field sensors known to those of ordinary skill in theart, or any other sensor known to those of ordinary skill in the art.

One such alternative embodiment sensor 1734 is shown in FIGS. 83-85.Sensor 1734 is preferably a tape sensor embedded in a resilient material1736, such as potting material, that provides a water proof cover tosensor 1734. Pedals 1660′ are provided with a rubber plunger 1738 thatpresses down on resilient material 1736 and moves contact strips 1740 ofsensor 1734 to close a circuit. When the circuit is closed, controlsystem 44 detects that the respective pedal 1660 is in the secondlowered position. When the respective pedal 1660′ is released, contactstrips 1740 separate and the circuit is open. Control system 44 detectsthe open circuit and recognizes that the respective pedal 1660′ hasmoved away from the second lowered position. Additional detail of a tapeswitch are provided in U.S. Pat. No. 4,539,560, to Fleck et al, thedisclosure of which is expressly incorporated by reference herein.

Another such alternative embodiment sensor 1742 is shown in FIGS. 86-88.Sensor 1742 is preferably a dome switch sensor embedded in a resilientmaterial 1736, such as potting material, that provides a water proofcover to sensor 1742. Pedals 1660′ are provided with rubber plunger 1738that presses down on resilient material 1736 and moves dome 1744 ofsensor 1734 that is mounted to a circuit board 1746 to close a circuit.An alternative plunger or actuator 1748 is shown in FIG. 86 that has adiameter of 0.118 inches. When the circuit is closed, control system 44detects that the respective pedal 1660′ is in the second loweredposition. When the respective pedal 1660′ is released, dome 1744 returnsto its normal position and the circuit is open. Control system 44detects the open circuit and recognizes that the respective pedal 1660′has moved away from the second lowered position. The preferredembodiment dome switch sensor is a Cannon SD 350 Dome Switch thatrequires 2.25 N operating forces and is sold by Cannon, ITT Industries.

Another such alternative embodiment sensor 1750 is shown in FIGS. 89-91.Sensor 1750 is preferably a force sensing resistor having its contactswith a cable 1752 embedded in a resilient material 1754, such as pottingmaterial, that provides a water proof cover to the contact. Pedals 1660′are provided with rubber plunger 1738 that presses down on sensor 1750and creates force on sensor 1750. When force is applied to sensor 1750,the overall electrical resistance of sensor 1750 changes. This change isresistance is monitored by the control system 44. When the resistancereaches a predetermined value, control system 44 detects that therespective pedal 1660′ is in the second lowered position. When therespective pedal 1660′ is released, the resistance returns to its normalvalue and control system 44 recognizes that the respective pedal 1660′has moved away from the second lowered position. Preferably, enoughforce is required that accidental lowering of the respective foot pedal1660′ will not change the resistance to the predetermined value.Furthermore, this force will preferably be greater that what a typicalchild can generate to avoid activation by children. According to analternative embodiment, once the predetermined resistance is reached,the speed at which the function operates is controlled by the amount offorce applied to the pedal 1660′ which controls the amount of resistanceof the sensor 1750 above the predetermined value. For example, if theforce applied creates a resistance just above or at the predeterminedvalue, the function, such as lowering the patient support 10, will occurslowly. However, if more force is applied and the resistance isincreased above the predetermined value, the speed of the patientsupport lowering will increase proportionally with the amount of forceapplied to the pedal 1660′. Thus, if a smaller force is applied, thepatient support 10 will lower slowly. If a greater force is applied, thepatient support 10 will lower faster. If an even greater force isapplied, the patient support 10 will lower even faster. Preferably, thefunction will have a maximum speed that cannot be exceeded regardless ofthe amount of force applied.

Obstacle Detection Device

Referring now to FIGS. 1, 2, and 57, the obstacle or interferencedetection device 58 is shown as coupled to the base frame 28 of thepatient support 10. The obstacle detection device 58 illustrativelyincludes first and second sensors 1802 and 1804 which are coupled to topsurfaces 474 and 476 of the longitudinally extending first and secondside members 192 and 194 of the base frame 28, respectively. While inthe following description, first and second sensors 1802 and 1804 areillustrated as being associated with the side members 192 and 194 of thepatient support 10, it should be appreciated that additional sensorscould be positioned adjacent the head end 25 and the foot end 27 of thepatient support 10.

Each sensor 1802 and 1804 is configured to provide an obstacle detectionsignal to control system 44 in the event that it detects an obstacle ordetermines that a fault condition exists. More particularly, each sensor1802 and 1804 is configured to provide the obstacle detection signal tocontrol system 44 upon detecting that an object, such as an individual'sfoot, is supported on one of the upper surfaces 474 and 476 of the baseframe 28.

In response to the obstacle detection signal from either of sensors 1802or 1804, control system 44 will prevent the lowering of the intermediateframe 32 relative to the base frame 28. Moreover, the obstacle detectionsignal indicates that either an obstacle is supported on the base frame28 or that at least one of the sensors 1802 or 1804 is not operatingproperly and is in a fault condition. As such, in order to avoidpotential damaging impact with the detected obstacle, control system 44prevents actuators 48 a and 48 b from operating to lower theintermediate frame 32. In an illustrative embodiment, control system 44permits continued operation of the actuators 48 a and 48 b to raise theintermediate frame 32. Further, upon receiving the obstacle detectionsignal, control system 44 may instruct the actuators 48 a and 48 b toraise the intermediate frame 32 for a predetermined time period,illustratively 2 seconds, while preventing operation of the actuators 48a and 48 b to lower the intermediate frame 32. Raising the intermediateframe 32 for a time period after an obstacle has been detected, providesfor the immediate and automatic movement of the frame 32 in a directionaway from the detected obstacle.

While the sensors 1802 and 1804 of the obstacle detection device 58 areillustratively positioned on the base frame 28, it should be appreciatedthat the sensors 1802 and 1804 could likewise be positioned on a lowersurface of the intermediate frame 32. Further, the obstacle detectiondevice 58 may be utilized to detect obstacles between any two portionsof a patient support 10 which move relative to each other. For example,the obstacle detection device 58 may be used between the head end andfoot end siderails 20 and 22, between the head end siderails 20 and theheadboard 16, and between the foot end siderails 22 and the footboard18.

Additional details of suitable obstacle detection devices are providedin U.S. Provisional Patent Application Ser. No. 60/373,819, title“Hospital Bed Obstacle Detection Device and Method”, filed Apr. 19,2002, and PCT International Patent Application No. PCT/US03/12166,titled “Hospital Bed Obstacle Detection Device and Method”, filed Apr.21, 2003, the disclosures of which are expressly incorporated byreference herein.

First Illustrative Embodiment Mattress Assembly

Referring now to the FIG. 92, the modular mattress 14 according to anillustrative embodiment of the present invention includes an outer cover2102 having a bottom cover portion 2104 and a top cover portion 2106configured to encapsulate a plurality of internal components including afoam receiving base 2108. The receiving base 2108 includes a footsection 2110 and a body section 2112 coupled to the foot section 2110 bya foot section securing substrate 2114. A component mounting substrate2116 is coupled to the body section 2112 of the base 2108. A foamcrowning core 2118 is supported above the mounting substrate 2116 and isreceived within the base 2108. A turn assist bladder assembly 2120 isreceived above the foam core 2118 and is coupled to the mountingsubstrate 2116. An upper bladder assembly 2122 is received above theturn assist bladder assembly 2120 and is likewise coupled to themounting substrate 2116. A fire sock or barrier 2124 is configured tosurround the receiving base 2108, including the foot section 2110 andthe body section 2112, the mounting substrate 2116, the foam core 2118,the turn assist bladder assembly 2120, and the upper bladder assembly2122. A shear cover 2125 is configured to be received over the firebarrier 2124. The top cover portion 2106 provides a patient rest surfaceand is configured to be coupled to the bottom cover portion 2104 todefine the outer cover 2102 and receive the other mattress components.Connectors 68 include a pair of mattress fluid connectors 2126 and 2127coupled to the bottom cover portion 2104 and provide fluid communicationbetween the manifold assembly 62, which is coupled to the pump 64, andthe mattress 14.

Mattress Foot Section Assembly

As detailed above, the leg section 42 of the deck 26 is extendable andretractable. FIGS. 93, 96, and 97 further illustrate the foot section2110 of the mattress 14 which is configured to extend and retract withthe movement of the adjustable length leg section 42 of the articulatingdeck 26. The foot section 2110 includes a base portion 2128 and a pairof opposing flange portions 2130 and 2132 supported above the baseportion 2128. The base portion 2128 includes angled side walls 2134 and2136 which are configured to conform to the angled side walls 291 a, 300a and 291 b, 300 b of the deck 26. The flange portions 2130 and 2132 areconfigured to extend out beyond the angled side walls 291 a, 300 a and291 b, 300 b of the deck 42. Illustratively, the foot section 2110 ismade of a resilient polyurethane foam.

The foot section 2110 is perforated to facilitate its longitudinalextension and retraction. More particularly, the foot section 2110 isformed to include a plurality of apertures, illustratively transverselyextending slots 2138 extending in a generally vertical direction throughthe base and flange portions 2130 and 2132, to facilitatecompressibility of the foot section 2110 in response to the retractionof the leg section 42 of the deck 26. More particularly, the pluralityof slots 2138 are arranged in a plurality of laterally extending rows2140 wherein the individual slots 2138 of each row are laterally offsetfrom those slots 2138 of longitudinally adjacent rows 2140. FIG. 96illustrates the foot section 2110 when the leg section 42 of the deck 26is in an extended position, wherein each slot 2138 widens to accommodatethe extension. As illustrated in FIG. 97, as the leg section 42 of thedeck 26 is retracted in the direction of arrow 2141, the foot section2110 likewise retracts and the slots 2138 narrow.

While in the illustrative embodiment, a plurality of discrete laterallyand longitudinally spaced transverse slots 2138 are illustrated tofacilitate retraction and extension of the foot section 2110, it shouldbe appreciated that other structures may be readily substitutedtherefor. More particularly, the foot section 2110 may be formed toinclude serpentine channels or other forms of openings, such as aplurality of slots extending substantially the full width of the footsection 2110 between opposing side edges of the flange portions 2130 and2132.

A foot section mounting plate 2142 is secured to a lower surface 2144 ofthe foot section 2110, illustratively through an adhesive bond. Asdescribed in greater detail below, the foot section mounting plate 2142provides a securing platform for a foot section anchor 2146 whichcouples the foot section to the leg section 42 of the deck 26 tofacilitate movement in cooperation therewith.

Heel Pressure Relief Member

The foot section 2110 includes a receiving recess 2148 extendingdownwardly from an upper surface 2150 of the base portion 2128 at a footend 2152 thereof. A heel pressure relief member 2154 is configured to bereceived within the recess 2148. As illustrated in FIGS. 94-97, the heelpressure relief member 2154 includes a sleeve or case 2156 and a fiberfill 2158 received within the sleeve 2156. With further reference toFIG. 94, the sleeve 2156 includes a closed first end 2160 and anopposing releasably closable second end 2162. More particularly, areleasable fastener 2164, such as a hook and loop fastener, may beutilized to secure the second end 2162 of the sleeve 2156.Illustratively, the sleeve 2156 is formed from a substantially airimpermeable material, such as a urethane coated twill. The fiber fill2158 illustratively comprises a material having high loft properties,such as a layered polyfill material. In operation, air enters the sleeve2156 through the hook and loop fastener 2164, thereby supplying thesleeve 2156 with air and providing air pressure for supporting the heelsof a patient. The air pressure within the pressure relief member 2154 isself-regulating as changes in force applied by the patient's heels willcause air to enter or exit the sleeve 2156 through the releasablefastener 2164.

An alternative embodiment heel pressure relief member 2154′ isillustrated in FIG. 95. In the alternative embodiment, a check valve2166 and a bleed orifice 2168 are received within the sleeve 2156. Theremainder of the member 2154′ is substantially air impermeable. Rapidinflation of the sleeve 2156 is provided by air passing through thecheck valve 2166. However, the check valve 2166 prevents the passage ofair therethrough from inside the sleeve 2156 to atmosphere. The bleedorifice 2168 permits for the slow passage of air from within the sleeve2156 to atmosphere, such that pressure within the pressure relief member2154′ may be optimized and self-regulated for each individual patient.

The heel pressure relief member 2154 is configured to reduce the levelof raised pressure between the patient's foot and the mattress. Moreparticularly, the pressure relief member 2154 provides for a region ofreduced pressure below the patient's heels. The foot section 2110includes a calf portion 2170 (FIG. 93) which supports the portion of thepatient's weight that would otherwise be supported by the patient's heeland thus reduces the overall interface pressure between the patient'sheel and the mattress 14. It is envisioned that the calf portion 2170 ofthe mattress 14 may include a transition zone where the materialstiffness of the foot section 2110 decreases in a longitudinal directionextending from a head end 2172 to the foot end 2152.

Mattress Body Section Assembly

The body section 2112 of the receiving base 2108 is further illustratedin FIG. 98 as including a bottom layer 2174 secured to longitudinallyextending first and second sidewalls or bolsters 2176 and 2178.Likewise, an end wall or bolster 2180 is coupled to the first and secondsidewalls 2176 and 2178. As such, the body section 2112 defines alongitudinally extending channel or bucket 2182 configured to receivevarious components of the mattress 14. As described in greater detailbelow, a fluid connector recess 2184 is formed near the head end 2186 ofthe body section 2112 and is configured to receive the mattress fluidconnectors 2126 and 2127.

The sidewalls 2176 and 2178 each include an angled or inclined portion2188 coupled to a flange portion 2190. The angled portions 2188 areconfigured to conform to the angled sidewalls 260 and 262 of the deck26, while the flange portions 2190 are configured to extend above andout beyond the sidewalls 260 and 262 of the deck 26. The body section2112 of the receiving base 2108 includes a head portion 2192 and a seatportion 2194 separated by a laterally extending slit 2196. Opposing endsof the slit 2196 include stress relief apertures 2198 formed within thesidewalls 2176 and 2178. As described in greater detail below, the slit2196 facilitates relative movement of the head and seat portions 2192and 2194 of the body section 2112 during articulation of the head andseat sections 38 and 40 of the deck 26.

Mattress Mounting Substrate

Turning now to FIGS. 99-101, the mounting substrate 2116 is receivedwithin channel 2182 defined by the body section 2112 of the receivingbase 2108. Opposing first and second end portions 2202 and 2204 of themounting substrate 2116 are secured to first and second lower mountingplates 2206 and 2208 (FIG. 98). The lower mounting plates 2206 and 2208are secured to a lower surface 2210 of the receiving base 2108. Moreparticularly, a plurality of fasteners, illustratively buttons 2212 aresecured to the lower mounting plates 2206 and 2208. The buttons 2212 arereleasably received within a plurality of substrate securing apertures2214 formed within the mounting substrate 2116, thereby connecting themounting substrate 2116 to the receiving base 2108 through the lowermounting plates 2206 and 2208. As detailed below, the lower mountingplate 2208 further provides a coupling platform for seat section anchors2219 which secure the seat portion 2194 of the receiving base 2108 tothe seat section 40 of the deck 26.

A plurality of turn assist bladder securing slots or apertures 2216 areformed proximate opposing longitudinally extending side edges 2222 and2224 of the mounting substrate 2116. As detailed below, the apertures2216 are configured to receive fasteners, such as buttons 2225 forsecuring the turn assist bladder assembly 2120 to the mounting substrate2116 (FIGS. 103, 114, and 115). Likewise, a plurality of upper bladderassembly securing slots or apertures 2226 are formed within the mountingsubstrate 2116 and are laterally spaced outside of the apertures 2216.Again, as detailed below, the apertures 2226 are configured to receivefasteners, such as buttons 2227 for securing the upper bladder assembly2122 to the mounting substrate 2116 (FIGS. 103, 114, and 115).

Foot Section Securing Substrate

With reference now to FIGS. 100 and 101, the foot section securingsubstrate 2114 includes a first portion 2228 secured to the seat portion2194 of the receiving base 2108 above the upper surface 2229 of themounting substrate 2116, and a second portion 2230 secured to the lowersurface 2144 of the foot section 2110. More particularly, the firstportion 2228 of the foot section securing substrate 2114 includes aplurality of mounting apertures 2232 configured to receive fasteners,such as buttons 2234. The buttons 2234 are secured to an upper mountingplate 2236 which is coupled to the upper surface 2237 of the receivingbase 2108, illustratively through an adhesive. The second portion 2230of the securing substrate 2114 is directly coupled to the lower surface2144 of the foot section 2110, illustratively through an adhesive. Thesecond portion 2230 includes a plurality of transverse slots 2238configured to be received in parallel disposition with the transverseslots 2138 formed within the foot section 2110.

Illustratively, the foot section securing substrate 2114 is formed froma flexible sheet material, such as pack cloth or urethane coated twill.As a flexible sheet material, the foot section securing substrate 2114may follow a serpentine path generally from a horizontal first plane ofthe upper surface 2229 of the mounting substrate 2116, vertically downaround a foot end edge 2240 of the receiving base 2108, and back along ahorizontal plane of the lower surface 2144 of the foot section 2110.

Foam Crowning Core

The foam crowning core 2118 is received within the channel 2182 definedby the sidewalls 2176 and 2178 of the body section of the receiving base2108. As shown in FIG. 102, the core 2118 may be composed of a pluralityof substantially planar layers 2244, 2246, 2248, 2250 of foam which areaffixed together using conventional means, such as an adhesive.Similarly, an upper crown layer 2251 is affixed to the upper surface oflayer 2250. Illustratively, the core 2118 is made of polyurethane foamhaving an indention force deflection (IFD) of between approximately 23to approximately 29. The crowning core 2118 defines a crowned uppersurface 2252 as illustrated in FIG. 102. Illustratively, a centerportion 2254 of the upper surface 2252 proximate the longitudinal centeraxis 2255 of the core 2118 is positioned vertically above the sideportions 2256 and 2258 of the crowned surface 2252 proximate opposingside walls 2260 and 2261 of the core 2118. More particularly, thevertical distance of the crowned surface 2252 between the center axis2255 and the side walls 2260 and 2261 is represented by the referenceletter A as shown in FIG. 102. Illustratively, the distance A is definedto be approximately 2 inches. In an alternative embodiment the distanceA is defined to be approximately 3 inches. The upper surface 2252 isarcuate as it extends from the side walls 2260 and 2261 toward thelongitudinal center axis 2255. The side walls 2260 and 2261 are angledto conform with the angled walls 2176 and 2178 of the receiving base2108.

The crowned surface 2252 is configured to facilitate lateral patienttransfer from the bed 10 to another patient support device positionedadjacent to the bed 10 by creating an inclined surface which provides aslight amount of gravity assistance when the caregiver is moving thepatient toward the side of the mattress 14. Additionally, since thesurface 2252 at the side walls 2260 and 2261 is lower than the centerportion 2254 of the mattress 14, the siderails 20 and 22 may have alower profile and still fulfill minimum height requirements. Moreparticularly, the distance from the top cover portion 2106 of themattress 14 above the side walls 2260 and 2261 of the crowning core 2118to the top of the siderails 20 and 22 is configured to be at leastapproximately 9 inches.

Turn Assist Bladder Assembly

With reference to FIGS. 92, 103, and 104, the turn assist bladderassembly 2120 is positioned above the crowning foam core 2118 andincludes partially overlapping first, or right and second, or leftinflatable turn assist bladders 2262 and 2264. As described in greaterdetail herein, each of the right and left turn assist bladders 2262 and2264 are selectively and individually inflatable to assist in theturning of a patient supported on the mattress 14. FIG. 103 illustratesboth the right and left turn assist bladders 2262 and 2264 in deflatedpositions, while FIG. 104 illustrates the right turn assist bladder 2262in a deflated position and the left turn assist bladder 2264 in aninflated position.

Each of the turn assist bladders 2262 and 2264 include an upper layer2266 and a lower layer 2268 coupled to the upper layer 2266. Inlet tubes2270 and 2272 are coupled to the manifold assembly 62 which, in turn, iscoupled to the pump 64 that provides pressurized air to inflate thechamber defined between the upper and lower layers 2266 and 2268.Sensing ports 2274 and 2276 are also provided in fluid communicationwith the chamber defined between the upper and lower layers 2266 and2268 of the turn assist bladders 2262 and 2264. The sensing ports 2274and 2276 are likewise in fluid communication with the manifold assembly62 which, in turn, is in fluid communication with a pressure sensor ortransducer 566 for detecting the pressure of air within the bladders2262 and 2264. The fill tubes 2270 and 2272 extend in a longitudinaldirection toward the head end 2186 of the receiving base 2108. Mountingtabs 2277 and 2279 are coupled to the fill tubes 2270 and 2272 andextend through the end wall 2180 of the receiving base 2108.Conventional fill ports or connectors 2281 are provided in fluidcommunication with the fill tubes 2270 and 2272. As illustrated in FIG.103, the fill tubes 2270, 2272 and the sensing ports 2274, 2276 arepositioned at opposing ends of the bladders 2262, 2264 in order for thepressure sensor 566 to receive a pressure reading from a location remotefrom the fill tubes 2270, 2272, thereby facilitating adequate pressurethroughout the bladders 2262, 2264.

As illustrated in FIG. 103, each turn assist bladder 2262 and 2264includes opposing longitudinally extending first, or right and second,or left side edges 2280 and 2282. The side edges 2280 and 2282 define apoint where the upper layer 2266 is coupled to the respective lowerlayer 2268. The right side edge 2280 of the left bladder 2264 overlapsthe left side edge 2282 of the right bladder 2262. In other words, eachof the bladders 2262 and 2264 have a portion extending over thelongitudinal center axis 2284 of the turn assist bladder assembly 2120.

Right and left mounting flanges 2286 and 2288 are coupled to opposingedges of the right and left turn assist bladders 2262 and 2264,respectively. Illustratively the mounting flanges 2286 and 2288 aresecured to the lower layers 2268 of the bladders 2262 and 2264 throughradio frequency (RF) welding. The mounting flanges 2286 and 2288 includea plurality of mounting apertures 2290 proximate their outside sideedges 2294 and 2296. Releasable fasteners, such as the buttons 2225identified above, are received within the apertures 2290 of the mountingflanges 2286 and 2288, and likewise are received within the apertures2216 of the mounting substrate 2116. As such, the turn assist bladderassembly 2120 is secured to the mounting substrate 2116. The turn assistbladder assembly 2120 may be made from a polyurethane film.

Upper Bladder Assembly

With reference to FIGS. 92 and 105-108, the upper bladder assembly 2122is positioned above the turn assist bladder assembly 2120, such that theturn assist bladder assembly 2120 is sandwiched between the foamcrowning core 2118 and the upper bladder assembly 2122 (FIG. 115). Theupper bladder assembly 2122 includes a head section or air zone 2302 anda seat section or air zone 2304, wherein each zone 2302 and 2304includes a plurality of laterally extending bladders 2306. A pluralityof baffles or walls 2308 separate the individual bladders 2306 in eachzone 2302 and 2304. Fluid passageways or ports 2310 are provided withinthe walls 2308 to provide for fluid communication between the bladders2306 within each zone 2302 and 2304. A solid wall or divider 2312 sealsthe bladders 2306 of the head zone 2302 from the bladders 2306 of theseat zone 2304.

The upper bladder assembly 2122 includes a longitudinally extendingcenter portion 2314 positioned intermediate longitudinally extendingfirst and second side portions 2316 and 2318. First and secondlongitudinally extending hinges 2320 and 2322 connect the center portion2314 to the first and second side portions 2316 and 2318, respectively.The hinges 2320 and 2322 provide increased flexibility to the inflatedupper bladder assembly 2122, thereby allowing the individual bladders2306 to generally follow the arcuate contour of the crowning core 2118.Further, the hinges 2320 and 2322 allow the inflated upper assembly 2122to conform to the general contour defined by the turn assist bladderassembly 2120 when it is inflated (FIGS. 114 and 115).

The upper bladder assembly 2122 further includes a peripheral mountingflange 2324 including a plurality of securing apertures 2326 forreceiving fasteners, such as buttons 2227. More particularly, thebuttons 2227 pass through the apertures 2218 formed in the mountingsubstrate 2116 and through the apertures 2326 formed in the mountingflange 2324, thereby securing the upper bladder assembly 2122 to themounting substrate 2116 (FIGS. 108 and 115). A pair of securing straps2330 and 2332 secure the head end of the upper bladder assembly 2122 tothe end wall 2180 of the receiving base 2108. More particularly, asshown in FIG. 109, a first end 2334 of each strap 2330 and 2332 iscoupled to the head end of the mounting flange 2324 through conventionalfasteners, such as buttons 2336. A second end 2338 of each strap 2230and 2232 is coupled to one of the mounting tabs 2277 and 2279 of thefill tubes 2270 and 2272 of the turn assist bladder assembly 2120, againthrough conventional fasteners, such as buttons 2340.

The upper bladder assembly 2122 may be formed by an upper sheet 2342 anda lower sheet 2344 coupled together at various locations by seals, suchas RF welds. More particularly, the welds may define the walls 2308 ofthe bladders 2306, the wall 2312 separating the head zone 2302 and thefoot zone 2304, and the mounting flange 2324.

The head zone 2302 is in fluid communication with a supply tube 2346that delivers pressurized air to the bladders 2306 and alternativelyexhausts pressurized air from the bladders 2306. A sensing line 2348 isalso provided in fluid communication with the head zone 2302 andprovides pressurized air to the pressure sensor 566 as detailed herein.Likewise, the seat zone 2304 is in fluid communication with a supplytube 2350 that delivers pressurized air to the bladders 2306 andalternatively exhausts pressurized air from the bladders 2306. A sensingline 2352 is also provided in fluid communication with the seat zone2304 and provides pressurized air to the pressure sensor 566.

Fire Barrier

Referring further to FIG. 92, the fire barrier 2124 receives thereceiving base 2108, the mounting substrate 2116, the crowning core2118, the turn assist bladder assembly 2120, and the upper bladderassembly 2122. The fire barrier 2124 includes an open end 2356configured to permit the fire barrier 2124 to slide over the othermattress components. Upon assembly, the open end 2356 of the firebarrier 2124 is closed utilizing conventional means, such as fasteners.The fire barrier 2124 may be made from a conventional fire-resistantmesh material, such as a fiberglass knit.

Shear Cover

With reference to FIGS. 92 and 110, the shear cover 2125 is configuredto fit over the above-identified mattress components as received withinthe fire barrier 2124. The shear cover 2125 is substantially planar, butfolded during assembly to form a top surface 2360, a sidewall 2362, andbottom inwardly extending flaps 2364. RF welded seams are utilized toform the four corners of the shear cover 2125 about the mattresscomponents. A belly band (not shown) may be wrapped laterally around theouter surface of the shear cover 2125 to assist in securing amid-portion thereof. The shear cover 2125 is configured to be locatedbetween the internal components and the top cover portion 2106 to permitthe top cover portion 2106 to slide easily over the mattress componentsand reduce shear forces between the patient's body and the mattress 14and reduce the likelihood of sacral breakdown.

The shear cover 2125 is formed from a material having a low coefficientof friction so that the mattress outer cover 2102 can slide relative tothe other mattress components. As the mattress 14 is articulated or asthe patient moves, the shear cover 2125 minimizes shear forces actingbetween the mattress top cover portion 2106 and the patient's body. Theshear cover 2125 may be made from a woven nylon or parachute material.Illustratively, the shear cover 2125 is made from a polyurethanematerial such as Deerfield urethane PT611OS having a thickness ofapproximately 0.002 inches. The polyurethane material provides aninexpensive shear material which reduces shear forces applied to thepatient's body situated on the mattress 14.

Outer Cover

Referring now to FIGS. 92 and 111, the top cover portion 2106 of theouter cover 2102 includes a top wall 2363 and a sidewall 2365. The topcover portion 2106 is illustratively formed from a ticking material,such as a stretchable polyurethane material which is resistant to fluidsand chemical stains.

The bottom cover portion 2104 includes a bottom wall 2366 and a sidewall2368. The sidewall 2368 is illustratively formed from a ticking materialsimilar to the sidewall 2365 of the top cover portion 2106. The sidewall2368 of the bottom cover portion 2104 is coupled to the sidewall 2365 ofthe top cover portion 2106, illustratively through RF welding.Illustratively, the bottom wall 2366 of the bottom cover portion 2104 isformed from a polyurethane coated twill material for enhanced wearresistance and to protect other components of the mattress 14 fromcontamination. The bottom wall 2366 includes an access panel 2370defined by a zipper 2372. The access panel 2370 is utilized duringassembly of the mattress 14 and further facilitates removal of thereplacement of the modular components of the mattress 14.Illustratively, the zipper 2372 is RF welded to the bottom wall 2366. Inan alternative embodiment of the invention, the zipper 2372 may beutilized to couple the sidewall 2368 of the bottom cover portion 2104 tothe sidewall 2365 of the top cover portion 2106.

With further reference to FIGS. 111-113, the bottom cover portion 2104includes a stress relief zone 2374 of extra material, which isillustratively pleated, to accommodate movement of the head section 38of the deck 26 relative to the seat section 40 of the deck 26. Moreparticularly, as the head section 38 is elevated relative to the seatsection 40, the head portion 2192 of the receiving base 2108 movesrelative to the seat portion 2194 of the receiving base 2108. The slit2196 and stress relief apertures 2198 and 2200 reduce the stress appliedto the receiving base 2108 during this movement. Likewise, the stressrelief zone 2374 of the bottom cover portion 2104 reduces stress withinthe outer cover 2102 of the mattress 14. As the mattress 14 bends tofollow the contour of the deck 26, the extra material within the stressrelief zone 2374 accounts for the increased distance between the headportion 2192 and the seat portion 2194 proximate the bottom coverportion 2104 as illustrated in FIGS. 112 and 113.

Mattress Anchors

Referring now to FIGS. 98 and 111, the seat section anchors 2219 arepositioned below the bottom cover portion 2104 of the mattress 14 andare coupled to the mounting plate 2208 fixed to the receiving base 2108.Illustratively, the anchors 2219 comprise laterally extending magnetsreceived within recesses 2376 formed in the seat section 40 of the deck26. As such, the anchors 2219 are attracted to the metal deck 26 andessentially “stick” thereto. Each anchor 2219 includes a plurality ofmounting apertures 2378 for receiving conventional fasteners, such asscrews 2379, which are threadably received within mounting apertures2380 formed in the mounting plate 2208. The mounting apertures 2380 areillustratively concentrically formed within locating protuberances orcones 2382 (FIG. 96). The locating cones 2382 facilitate properplacement of the anchors 2119 during assembly.

With reference to FIGS. 93 and 111, the foot section anchor 2146 issecured to the foot section 2110 of the mattress 14 below the bottomcover portion 2104 through conventional fasteners, such as screws 2383.The foot section anchor 2146 illustratively comprises a resilient tabhaving opposing ends 2384 and 2386 which may be flexed away from themattress 14 and placed under retaining arms 2387 formed within the legsection 42 of the deck 26.

Manifold Assembly and Mattress Connectors

The pair of mattress fluid connectors 2126 and 2127 are secured to thebottom cover portion 2104 and are received within the connector recess2184 formed within the receiving base 2108. Each connector 2126 and 2127includes a plurality of barbed fittings 2388 which are sealinglyreceived within flexible tubing 2390 illustratively connected to one ofthe right turn assist bladder 2262, the left turn assist bladder 2264,the head zone 2302 of the upper bladder assembly 2122, and the seat zone2304 of the upper bladder assembly 2122. Additional details regardingthe mattress fluid connectors 2126 and 2127 are provided below inconnection with the manifold assembly 62.

FIGS. 114 and 115 illustrate operation of the mattress 14 including theupper bladder assembly 2122 and the turn assist bladder assembly 2120.More particularly, FIG. 114 illustrates a normal mode of operation withthe head zone 2302 of the upper bladder assembly 2122 inflated, and theturn assist bladders 2262 and 2264 deflated. FIG. 115 illustrates a leftturn assist mode of operation wherein the left turn assist bladder 2264is inflated. Since the left turn assist bladder 2264 is laterally offsetfrom the longitudinal center axis 2284 of the mattress 14, inflation ofthe bladder 2264 causes one side of the upper bladder assembly 2122 toraise above the other side. The hinges 2320 and 2322 between the sideportions 2316 and 2318 and the center portion 2314 of the bladders 2306of the upper bladder assembly 2122 permit the mattress 14 tosubstantially conform to the shape resulting from the inflation of theleft turn assist bladder 2264. In an illustrative embodiment, uponinflation of one of the turn assist bladders 2262 and 2264, a patientsupported on the mattress 14 is rotated by an angle α of approximately20 degrees from horizontal. Upon completion of the turn assist, thecontrol system 44 causes the inflated turn assist bladder 2262, 2264 tovent to atmosphere. Simultaneously, the upper bladder assembly 2122 isinstructed by the central system 44 to inflate to a maximum pressure.Since the turn assist bladder assembly 2120 is sandwiched intermediatethe upper bladder assembly 2122 and the crowning core 2218, inflation ofthe upper bladder assembly 2122 facilitates the rapid venting of airwithin the turn assist bladders 2262 and 2264 to atmosphere.

Referring now to FIGS. 116-119, an illustrative embodiment manifoldassembly 62 for use in connection with the mattress 14 is shown. Themanifold assembly 62 is configured to provide fluid communicationbetween the pump 64 and the air mattress 14. The manifold assembly 62includes first and second manifolds 2402 and 2404 configured to controlthe supply of air to and the exhaust of air from the controlled airzones of the mattress 14. Air is supplied to the manifolds 2402 and 2404by the pump 64, while air is exhausted to atmosphere 2405 through themanifolds 2402 and 2404. More particularly, the manifolds control airpressure within the right turn assist bladder 2262, the left turn assistbladder 2264, the head zone 2302 of the upper bladder assembly 2122, andthe seat zone 2304 of the upper bladder assembly 2122. While in FIGS.116-119, first and second manifolds 2402 and 2404 are positioned inspaced relation, it should be appreciated that in other embodiments,such as described herein, a single manifold may be utilized.

With further reference to FIGS. 116 and 117, a separate valve assembly2406, comprising first and second solenoid actuated pilot valves 2408and 2410, are provided for each controlled air zone 2262, 2264, 2302,and 2304 of the mattress 14. The valve assembly 2406 a for controllingthe head zone 2302 of the upper bladder assembly 2122 is coupled to thefirst manifold 2402 and includes a normally closed pilot valve 2408 afor controlling the air intake and a normally closed pilot valve 2410 afor controlling the air exhaust. The valve assembly 2406 b forcontrolling the seat zone 2304 of the upper bladder assembly 2122 islikewise coupled to the first manifold 2402 and includes a normallyclosed pilot valve 2408 b for controlling the air intake and a normallyclosed pilot valve 2410 b for controlling the air exhaust.

The valve assembly 2406 c for controlling the right turn assist bladder2262 is coupled to the second manifold 2404 and includes a normallyclosed pilot valve 2408 c for controlling air intake and a normally openpilot valve 2410 c for controlling the air exhaust. Likewise, the valveassembly 2406 d for controlling the left turn assist bladder 2264 iscoupled to the second manifold 2404 and includes a normally closed pilotvalve 2408 d for controlling air intake and a normally open pilot valve2410 d for controlling the air exhaust. An optional valve assembly 2406e is illustrated as coupled to the first manifold 2402 and may includepilot valves 2408 e and 2410 e, as desired, to control optionaladditional air zones within the mattress 14.

In an illustrative embodiment, the normally closed pilot valves compriseSY series piloted valves, Model No. SY114-5GZ available from SMCCorporation of Indianapolis, Ind. Likewise, in an illustrativeembodiment of the invention, the normally open pilot valves comprise SYSeries piloted valves, Model No. SY124-5GZ available from SMCCorporation of Indianapolis, Ind.

With further reference now to FIGS. 116-119, air supplied from the pump64 passes through a conventional fluid T-connector 2412 which separatesthe air flow to the first and second manifolds 2402 and 2404 throughfirst and second supply tubes 2414 and 2416. Once entering each manifold2402 and 2404, the supplied air is routed through to the various valveassemblies 2406.

Details of the valve assembly 2406 c for controlling air pressure withinthe right turn assist bladder 2262 is illustrated in FIG. 119. It shouldbe appreciated that the valve assembly 2406 d for use with the left turnassist bladder 2264 is identical. Further, the valve assemblies 2406 aand 2406 b for use with the head zone 2302 and the seat zone 2304 of theupper bladder assembly 2122 are substantially the same except for thesubstitution of a second normally closed pilot valve for the normallyopen pilot valve 2410 c of the valve assembly 2406 c.

With reference to FIG. 119, air is supplied to the valve assembly 2406 cby a fill port 2418 which is in communication with the pump 64. The fillport 2418 is in fluid communication with an accumulator port 2420through a check valve (not shown). The check valve provides for air flowfrom the fill port 2418 to the accumulator port 2420 but prevents airflow in the reverse direction. The check valve therefore helps maintainpressure within the accumulator port 2420 should pressure be lost in thefill port 2418, for example, if the pump 64 would stop operating. Theaccumulator port 2420, in turn, is in fluid communication with the upperpilot pressure chamber 2422 of the first pilot valve 2408 c.

Each pilot valve 2408 c and 2410 c includes a conventional solenoid (notshown) received within a body portion 2424 and configured to move a pin2426. The first pilot valve 2408 c is normally closed, such that adiaphragm 2428 coupled to the pin 2426 sealingly engages a valve seat2430. The normally closed valve 2408 c includes a spring 2432concentrically disposed around the pin 2426 and biasing the diaphragm2428 downwardly into sealing engagement with the valve seat 2430. Assuch, air from the fill port 2418 may not pass to a supply port 2434connected to the right turn assist bladder 2262 of the mattress 14.However, upon activation, the solenoid is energized such that the pin2426 is pulled upwardly and the diaphragm 2428 moves away from the valveseat 2430. As such, a passageway represented by arrow 2436 is definedsuch that air may pass through the fill port 2418 over the valve seat2430 and through the supply port 2434 to the right turn assist bladder2262.

At the same time that the normally closed valve 2408 c is activated, thenormally open valve 2410 c is likewise activated such that the solenoidis energized to push its pin 2426 downwardly thereby causing thediaphragm 2418 to sealingly engage the valve seat 2430. As such, thesupply port 2434 is sealed off from an exhaust port 2438 in fluidcommunication with atmosphere. In the normally open valve 2410, thespring 2432 is concentrically received within a portion of the supplyport 2434 and is configured to bias against the diaphragm 2428 to pushthe diaphragm 2428 away from the valve seat 2430 such that the supplyport 2434 is in fluid communication with the exhaust port 2438.

The sensing ports or lines 2274, 2276, 2348, and 2352 from thecontrolled air zones 2262, 2264, 2302, and 2304 of the mattress 14 arecoupled in fluid communication with the first and second manifolds 2402and 2404 as shown in FIG. 116. Each sensing line 2274, 2276, 2348, and2352 supplies air which illustratively passes through fluid sensingports 2439 formed within the first and second manifolds 2402 and 2404and then exits through pressure sensing tubes 2440. Each tube 2440 iscoupled to a pressure sensor or transducer 566 supported on a valvecontroller circuit board 2444. The circuit board 2444 is illustrativelypositioned intermediate the first and second manifolds 2402 and 2404.The circuit board 2444 is in communication with the control system 44and, as such, provides signals to the control system 44 indicative ofpressure within the various controlled air zones 2262, 2264, 2302, and2304 of the mattress 14. Additional details regarding the control of thevalve assemblies 2406 in response to pressure within the variouscontrolled air zones of the mattress 14 is provided herein.

With reference to FIGS. 16, 118, 120, and 121, connectors 70 includefirst and second manifold or receiving connectors 2450 and 2452 coupledto the first and second manifolds 2402 and 2404. The partition wall 274coupled to the deck 26 is positioned intermediate the manifoldconnectors 2450 and 2452 and the manifolds 2402 and 2404. The manifoldconnectors 2450 and 2452 are configured to sealingly mate with themattress connectors 2126 and 2127, respectively. Each manifold connector2450 and 2452 includes a plurality of outlets 2454 and 2456 configuredto sealingly receive plugs 2458 and 2460, respectively, of the matingmattress connector 2126 and 2127. While FIG. 120 illustrates manifoldconnector 2450 and mattress connector 2126, it should be noted thatmanifold connector 2452 and mattress connector 2127 are substantiallyidentical to manifold connector 2450 and mattress connector 2126.

The outlets 2454 are in fluid communication with the supply ports 2434of the valve assemblies 2406, while the plugs 2458 are in fluidcommunication with the intake ports 2270, 2272, 2346, and 2350 of thevarious controlled air zones 2262, 2264, 2302 and 2304 of the mattress14 in the manner detailed herein. The outlets 2456 are in fluidcommunication with the pressure sensing tubes 2440 through the manifolds2402 and 2404, while the plugs 2460 are in fluid communication with thesensing lines 2274, 2276, 2348, and 2352 of the controlled air zones ofthe mattress 14. In an alternative embodiment of the invention, thesensing lines 2274, 2276, 2348, and 2352 may bypass the manifolds 2402and 2404 and be directly connected to the pressure sensors 2442.

Each of the plugs 2458 and 2460 illustratively includes an O-ring gasket2462 and 2463 to promote sealing with a mating outlet 2454 and 2456,respectively. The mattress connectors 2126 and 2127 each include aperipheral inner flange 2464 which is configured to be received within aperipheral outer flange 2466 of a respective manifold receivingconnector 2450 and 2452. A fastener, illustratively a u-shaped staple2468 locks the peripheral flanges 2464 and 2466 together. Moreparticularly, the inner flange 2464 includes apertures 2470 and theouter flange 2466 includes apertures 2472 which are coaxially alignedwith the apertures 2470 when the mattress connector 2126, 2127 isproperly seated within the mating manifold receiving connector 2450,2452. The staple 2468 includes a pair of legs 2474 which are receivedwithin the aligned apertures 2470 and 2472 to lock the connectors. Whilea staple 2468 is illustrated, it should be appreciated that otherfasteners, such as latches, may be readily substituted therefor.

As described above, the manifold receiving connectors 2450 and 2452 arecoupled to the manifolds 2402 and 2404, respectively, through thepartition wall 272. Conventional fasteners, such as screws 2476, may beutilized to secure the manifold receiving connectors 2450 and 2452 andthe first and second manifolds 2402 and 2404 relative to the partitionwall 272. In one illustrative embodiment, cylindrical gaskets may bepositioned intermediate each outlet 2454 of the receiving connectors2450 and 2452 and the manifold 2402 and 2404 in order to effect sealingtherebetween.

In a further illustrative embodiment, a gasket 2502 such as that shownin FIGS. 122 and 123 may be positioned intermediate the manifoldconnectors 2450 and 2452 and the vertical wall 274 of partition 272. Thegasket 2502 includes a rigid substrate 2504 supporting a perimeter seal2506. Likewise, the substrate 2504 supports a plurality of outlet seals2508. The outlet seals 2508 extend outwardly from a first surface 2510of the substrate 2504. Illustratively, the substrate 2504 is molded as asingle piece of vulcanized fiber paper. Further illustratively, theperimeter seal 2506 and the outlet seals 2508 are formed from a neoprenematerial of approximately 25 durometer.

The outlet seals 2508 pass through apertures formed within the verticalwall 274 of partition 272 and are compressed between the manifoldconnectors 2450 and 2452 and the manifolds 2402 and 2404. Each outletseal 2508 includes first and second pairs of annular sealing rings 2512and 2514 which extend in opposite directions (FIG. 123). Moreparticularly, the first pair of sealing rings 2512 is configured to becompressed against the respective manifold connector 2450 and 2452,while the second pair of sealing rings 2514 is configured to becompressed against the respective manifold 2402 and 2404. FIG. 123illustrates an outlet seal 2508 in an uncompressed state in order toillustrate the expected amount of compression by the manifold 2402 andthe manifold connector 2450.

The gasket assembly 2502 provides for a rigid substrate 2504 which doesnot compress during assembly and thereby provides for a definite torquespecification or tightening of the receiving connectors 2450 and 2452against the respective manifolds 2402 and 2404. Likewise, the rigidsubstrate 2504 provides for a positive seal and accounts for variationsor discrepancy in material dimensions. The individual cylindrical outletseals 2508 provide for zone controlled sealing and preventcross-communication between the various outlets 2454. Finally, theperimeter seal 2506 provides secondary sealing and preventscontamination within the receiving connectors 2450 and 2452 by dirt orother contaminants.

Pressure Control System

As mentioned elsewhere in this disclosure, control system 44 includesdynamic surface module 518. In addition to other functions, dynamicsurface module 518 includes a pressure control system 3000. As shown inFIG. 124, pressure control system 3000 includes a plurality valvesolenoids 564, a plurality of pressure sensors or transducers 566, ananalog to digital converter 3002, a microcontroller 3004, a power supply3006 and pump 64. Microcontroller 3004 includes memory 3010 and centralprocessing unit 3012.

Pressure sensors, illustratively transducers 566, periodically sense thepressure in one or more of controlled air zones 2262, 2264, 2302, 2304of mattress 14 and output a voltage proportional to the amount ofpressure that is sensed. Analog-to-digital converter 3002 converts thevoltage to digital form and feeds the digital value to microcontroller3004. Microcontroller 3004 analyzes the current pressure and determineswhether the current pressure in controlled air zones 2262, 2264, 2302,2304 is correct, too high, or too low in comparison to a desiredpressure. Memory 3010 stores data, e.g. in the form of look-up tables,which is used in this analysis. For example, the desired pressure of anair zone 2262, 2264, 2302, 2304 may depend upon the particular operatingmode of the system 3000 (e.g., pressure relief, max-inflate, CPR, rightturn assist, or left turn assist), whether head section 38 is elevatedand the degree of elevation, and/or the size of the patient. Tables 1,2, and 3 show examples of desired pressures for controlled air zones2262, 2264, 2302, 2304 based on the air system operating mode, patientsize, and, for seat section 42, head section elevation.

TABLE 1 HEAD SECTION (Pressure measured in inches H₂O) PT. SIZE MODE SMMED LG Pressure Relief* 5-7 7-9 11-13 Max Inflate 26.5-27.5 CPR 20-30Right-Left Turn Assist* 5-7 7-9 11-13 Post-Turn Assist 20-22 *May varyaccording to head angle.

TABLE 2 SEAT SECTION** (Pressure measured in inches H₂O) PT. SIZE MODESM MED LG Pressure Relief 7-21 9-25 13-31 Max Inflate 25-29 CPR 20-30Right-Left Turn Assist 7-21 9-25 13-31 Post-Turn Assist 20-22 Seat Boost23-25  27-29  33-35 **Pressure also varies with head elevation - seeTable 4.

TABLE 3 TURN ASSIST BLADDERS (Pressure measured in inches H₂O) PT. SIZEMODE SM MED LG Pressure Relief — — — Max Inflate — — — CPR — — —Right-Left Turn Assist 18-24 22-28 27-33

If the pressure of an air zone 2262, 2264, 2302, 2304 is too high,microcontroller 3004 actuates the appropriate valve assembly 2406 toallow air to escape from the air zone 2262, 2264, 2302, 2304. If thepressure is too low, microcontroller 3004 sends a message over network510 to power supply module 514 of patient support 10 (parts of which aregenerally depicted in FIG. 124 as power supply 3006), and power supply3006 activates pump 64. When microcontroller 3004 detects that pump 64is turned on, it actuates the appropriate valve assembly 2406 to allowair to enter the appropriate controlled air zone 2262, 2264, 2302, 2304.

Among other things, embodiments of pressure control system 3000illustratively include one or more of the following features: a process3030 for controlling the inflation of controlled air zones 2262, 2264,2302, 2304 according to the size of a patient, a process 3032 forcontrolling inflation of turn assist bladders 2262, 2264, and/or aprocess 3070 for controlling inflation of seat section 40 in response toelevation of head section 38.

Mattress Pressure Determination

In certain embodiments of pressure control system 3000 of dynamicsurface module 518, a process 3030 for controlling the inflation ofcontrolled air zones 2262, 2264, 2302, 2304 according to the size of apatient disposed on patient support 10 is provided. One embodiment ofprocess 3030 is shown in FIG. 125 and described below.

Process 3030 begins at step 3014 of FIG. 125, where the microcontroller3004 detects whether it has been activated to determine patient size. Inone illustrative embodiment, patient size button 1628 of siderailcontrollers 52, 54 is optional. In other embodiments, button 1628 is notoptional and the operator or caregiver is required to select anappropriate patient size. In still other illustrative embodiments,button 1628 automatically selects a default setting, e.g., the “medium”size, if a patient size is not selected by the operator or caregiver.

In the illustrative embodiment of FIG. 125, there are three possiblepatient sizes that can be selected by using button 1628: “small,”“medium,” and “large.” In general, the determination of whether apatient is of small, medium, or large size is made by the caregiver.However, it is understood that there are any number of different ways toindicate a patient's size. For example, in lieu of button 1628, pressurecontrol system 3000 may provide the ability to automatically determinethe patient's size based on the patient's weight, which may bedetermined by weigh frame 36 and/or by a force sensor located in seatsection 40 in the manner detailed herein. Another alternative is toprovide a user interface on siderail controllers 52,54 whereby thecaregiver may enter the patient's height, and system 3000 determines thepatient's size based on the entered height value and the patient'sweight.

At step 3016, the controlled air zone(s) 2262, 2264, 2302, 2304 beingmonitored is determined. All of head section air zone 2302, seat sectionair zone 2304, and turn assist bladders 2262, 2264 may be inflated tovarying pressures based on patient size. However, it is understood thatin alternative embodiments not all of air zones 2262, 2264, 2302, 2304may be inflated based on patient size.

At step 3018, process 3030 determines the desired inflation pressure forthe respective air zone(s) 2262, 2264, 2302, 2304 being monitored basedon the patient size. In the illustrated embodiment, microcontroller 3004obtains the desired pressure for the air zone(s) 2262, 2264, 2302, 2304from at least one look-up table stored in memory 3010. The desiredpressure may be a discrete value or a range of permissible values. Also,the desired pressure may be different for each air zone 2262, 2264,2302, 2304. Further, various other factors, including environmentalfactors such as temperature and/or altitude, may affect the desiredpressure values and be reflected in data in the look-up table. As anexample, in one embodiment, under normal hospital room conditions, for apatient considered “small,” the appropriate pressure is about 4-7 inchesin water for head section air zone 2302, about 7 to 21 inches in waterfor seat section air zone 2304, and about 18-24 inches in water for turnassist bladders 2262, 2264. Tables 1, 2, and 3 show examples of desiredpressure values based upon patient size.

As indicated by decision step 3020, in the illustrative embodiment ofFIG. 125, the appropriate pressure for seat section air zone 2304 alsodepends on the elevation of head section 38. If process 3030 causesinflation of seat section air zone 2304, then at step 3022 the pressureof seat section air zone 2304 is adjusted based on the angle of headsection 38. This adjustment is discussed in connection with FIG. 128below. Thus, for seat section air zone 2304, the appropriate pressure isdetermined by reference to both patient size and head angle. However,adjusting the pressure of seat section air zone 2304 based on only oneof these criteria is also within the scope of the present invention.

At decision step 3024, microcontroller 3004 measures the currentpressure as described above and determines whether the current pressureis less than, equal to, or greater than the desired pressure determinedas described above. If the current pressure is less than the desiredpressure at step 3026, microcontroller 3004 commands power supply 3006to activate pump 64 to inflate air zone 2304 to the desired pressure asdescribed above. If the current pressure is greater than the desiredpressure, then at step 3028, air zone 2304 are deflated as describedabove.

Patient Turn Assist

In addition to other functions discussed above and elsewhere in thisdisclosure, pressure control system 3000 of dynamic surface module 518controls the operation of turn assist bladders 2262, 2264. Turn assistbladders 2262, 2264 illustratively are bladders of mattress 14 thatselectively inflate to assist a caregiver in turning or rotating apatient, e.g., for therapy or treatment reasons. One embodiment of aprocess 3032 for controlling operation of turn assist bladders 2262,2264 is shown in FIGS. 126 and 127 as described below. Process 3032 isimplemented using application software stored in memory 3010 ofmicrocontroller 3004. The structure of illustrative turn assist bladders2262, 2264 is described above.

Process 3032 begins at step 3034 of FIG. 126, where microcontroller 3004detects whether a request has been received to activate one of turnassist bladders 2262, 2264. In the illustrated embodiment, such arequest is initiated by an operator or caregiver activating one of turnassist buttons 1624, 1626 located on siderail controllers 52, 54.However, it is understood that other means for activating the turnassist may be used. For example, control system 44 may be programmed toautomatically activate one or more of turn assist buttons 1624, 1626 atscheduled times during the day or night.

At decision step 3036, prior to initiating the turn assist function,process 3032 checks to make sure that the siderail(s) 20, 22 towardwhich the patient is being turned is in the up or raised position, basedon signals provided by siderail position detector(s) 60. If one or moreof siderails 20, 22 toward which the patient is being turned is not inthe up position (i.e. in down or lowered position), an error signal isgenerated at step 3038 and process 3032 returns to step 3034 withoutactivating the turn assist bladders 2262, 2264. In the illustrativeembodiment, an audible or visual signal is generated for a brief periodor until the siderail or siderails 20, 22 are brought to the upposition. Thus, in the illustrative embodiment, the siderails 20, 22toward which the patient is being turned must be in the up position inorder for the turn assist process to initiate. It is possible, however,that in other embodiments, a caregiver or operator may override thisrestriction, or that this restriction may be made optional, for example,depending on the circumstances of a particular patient.

At decision step 3040, microcontroller 3004 checks to see if the angleof head section 38 (head angle) is less than, equal to, or greater thana predetermined maximum angle. In the illustrated embodiment, themaximum head angle is about 40°. The head angle determination is made bylogic module 512 and is discussed in connection with FIG. 128 below.Logic module 512 reports the head angle to dynamic surface module 518for use in process 3032, via network 510. If the head angle is less thanor equal to 40°, then the turn assist process continues to step 3044.However, if the head angle is greater than about 40°, an error signal isgenerated at step 3042, and the turn assist process returns to block3034 without activating the turn assist bladders 2262, 2264.

At step 3044, the size of the patient being supported by patient support10 (e.g., small-medium-large) is determined as described above so that adesired pressure based on patient size is applied to the selected turnassist bladder 2262, 2264.

At step 3046, if first turn assist button 1624 is activated, first turnassist bladder 2262 inflates to rotate a person in patient support 10upwardly in a counter-clockwise from the perspective of a personstanding behind head section 38. If second turn assist button 1626 isactivated, second turn assist bladder 2264 inflates to rotate the personupwardly in the opposite direction as rotated in response to activationof first turn assist button 1624. Inflation of the selected turn assistbladder 2262, 2264 raises one side of the patient to a predeterminedangle. In the illustrated embodiment, the selected turn assist bladder2262, 2264 inflates to rotate the patient onto his or her side at abouta 20 degree angle with respect to mattress 14, in approximately 20-50seconds, depending on the size of the patient. It is understood that thepredetermined angle and speed of inflation may be changed or modified asneeded based on a variety of factors, including the purpose for rotatingthe patient.

A timer, illustratively part of the central processing unit 3012, is setat step 3048 when the selected turn assist bladder 2262, 2264 isinflated. The selected turn assist bladder 2262, 2264 remains inflatedfor a predetermined period of time, for example 5-30 seconds. In theillustrated embodiment, the duration of turn assist inflation is about 5seconds. At step 3050 the timer counts out this wait period. After thewait period is complete (e.g., after 5 seconds), an audible or visualsignal is generated to indicate to the patient and caregiver that theselected turn assist bladder is about to enter a “post-turn assist”phase. Process 3032 then begins deflating the selected turn assistbladder 2262, 2264 at step 3052. In the illustrated embodiment,deflation is expedited by quickly “hyperinflating” bladders 2302, 2304to a firm, “post-turn assist” inflation pressure (see, e.g., Table 1 andTable 2). Inflation of bladders 2302, 2304 exerts pressure on turnassist bladders 2262, 2264, causing turn assist bladders 2262, 2264 toexpel air more rapidly. Alternatively, a vacuum mechanism may be coupledto turn assist bladders 2262, 2264 to accelerate deflation.

The post-turn assist inflation and deflation processes may beinterrupted under certain circumstances. For example, when a patient'sbed 10 needs a linen change, it may be desirable for first and secondturn assist bladders 2262, 2264 to be activated in more rapid successionthan would be possible if the full post-turn assist process wereperformed. In such instances, if one of turn assist buttons 1624, 1626is activated, and then the other turn assist button 1624, 1626 isactivated before the previous turn assist process is complete, theprevious process is interrupted and, as long as the turned-to-sidesiderails 20, 22 are in the up position as described above, and headsection 38 is positioned at an angle less than or equal to 40°, the newturn assist mode is started.

For example, assume a caregiver presses first turn assist button 1624.If the caregiver then presses second turn assist button 1626 while firstturn assist bladder 2262 is inflating, then process 3032 will interruptthe inflation, bypass the post-turn assist phase (i.e., head and seatbladders 2302, 2304 will not be inflated), and begin inflating secondturn assist bladder 2264 as long as siderails 20, 22 are up on the sideof the bed the patient is being turned to, and the head angle is lessthan or equal to the maximum head angle. If the caregiver presses secondturn assist button 1626 while first turn assist bladder 2262 is inpost-turn assist mode, post-turn assist mode is interrupted and secondturn assist bladder 2264 begins inflating as discussed above.

Monitor activity step 3060 is a step that is periodically executedduring the turn assist operation. The monitor activity process 3060 isshown in more detail in FIG. 127. This process 3060 detects whether apatient or caregiver attempts to utilize other bed features while eitherturn assist bladder 2262, 2264 is in operation. For example, at step3062, process 3032 checks to see if siderail 20, 22 on the side to whichthe patient is being turned is raised or lowered. In the illustratedembodiment, if siderails 20, 22 are in the raised position at thebeginning of turn assist, but one or more of them are lowered duringturn assist, an audible signal or alarm is generated for a brief periodat step 3064, or until the siderail 20, 22 is returned to the raisedposition, but the turn assist process 3032 is not interrupted. Inalternative embodiments, however, upon detecting a lowering of siderail20, 22, the turn assist process 3032 may be suspended for a brief periodor stopped until or unless the lowered siderail 20, 22 is returned tothe raised position.

At step 3066, process 3060 detects whether a patient or caregiver hasselected another mode, e.g., turn assist for the other side of thepatient, max inflate, or pressure relief. During the turn assistoperation, the selection of another mode causes process 3060 to beginexiting the turn assist mode at block 3067. If the other turn assistmode is selected, the current turn assist bladder 2262, 2264 is deflatedand the other turn assist mode is entered substantially immediately. Ifthe pressure relief mode or the max-inflate mode is selected, process3060 immediately enters the post-turn assist operation and enters thenewly selected mode upon completion of the post-turn assist phase.However, if the CPR function is activated, process 3060 immediatelydeflates turn assist bladder 2262, 2264 and enters the CPR modesubstantially immediately. If no mode is selected during turn assist,process 3060 will exit as described previously and enter the pressurerelief mode upon completion of the post-turn assist phase.

At step 3068, process 3060 detects whether the angle of head section 38has been increased above the maximum head angle as described above. Ifthe head angle increases above the maximum head angle, an error message,e.g., in the form of an audible or visual signal, is generated at step3069. In the illustrated embodiment, the turn assist process 3032 isinterrupted if the head angle exceeds the maximum angle. In alternativeembodiments, the turn assist process 3032 is not interrupted.

Head Section Elevation

In addition to other functions discussed above and elsewhere in thisdisclosure, pressure control system 3000 may include another process3070 for controlling the inflation of seat section air zone 2304according to the position of head section 38. One embodiment of suchmethod is shown in FIG. 128 and described below.

When head section 38 is elevated, a portion of the patient's weightnaturally shifts from head section 38 to seat section 40. To anticipatethis weight shift and prevent “bottoming out,” the inflation pressure ofseat section air zone 2304 is adjusted in response to changes in theposition of head section 38. Table 4 below shows pressure ranges forseat section air zone 2304 depending on both patient size and angle ofelevation of head section 38.

TABLE 4 SEAT SECTION PRESSURE RANGES BY HEAD ANGLE HEAD PT. SIZE ANGLE(°) SM MED LG  0-10 7-9  9-11 13-15  6-20  9-11 11-13 15-17 16-30 11-1313-15 17-19 26-40 13-15 15-17 19-21 36-50 15-17 17-19 21-23 46-60 17-1919-21 25-27   56-65+ 19-21 23-25 29-31

At step 3072 of FIG. 128, the position of head section 38, or headangle, is determined by position detector 606. In the illustrativeembodiment, a potentiometer reading corresponding to the head angle isdetermined by logic module 512 and reported to dynamic surface module518 via network 510 for use in process 3070. In the illustratedembodiment the potentiometer reading is a value ranging from 0 to 255. Achange of 10 counts has been determined to indicate a change ofapproximately 3 degrees of head angle in the illustrated embodiment. Thepotentiometer 624 in the motor housing of actuator 48 c, which operatesto raise and lower head section 38 varies proportionally with movementof the motor drive shaft 172 c while actuator 48 c is operating. Thelogic module 512 measures a change in voltage across potentiometer 624in a voltage divider circuit and converts it to a digital value usingA/D converter 620. The corresponding head angle is determined in process3070 by reference to a look-up table stored in memory 3010. Table 5below shows examples of the head angle values and their correspondingpotentiometer readings. While a potentiometer 624 is used in theillustrated embodiment, it is understood that a tachometer or othermeans for determining head angle are equally suitable.

TABLE 5 HEAD ANGLE VALUES REGION POT. VALUE HEAD ANGLE ° 0  0-51  0-10 141-76  6-20 2  60-100 16-30 3  90-122 26-40 4 112-142 36-50 5 132-15746-60 6 147-255   56-65+

At decision step 3074, process 3070 evaluates the input received fromlogic module 512 and determines whether head section 38 has experiencedat least a 3 degree change in position by comparing the current headangle to the previous head angle. If the head angle has changed at leastapproximately 3 degrees, the process 3070 continues to step 3076. If nochange or less than approximately 3 degrees change in either directionhas occurred, process 3070 returns to step 3072. It is understood that 3degrees is an exemplary value and that a change in the head angle may beindicated by a greater or lesser value as appropriate. Of course, duringthis time, pressure control system 3000 continues to periodicallymeasure the pressure of seat section air zone 2304 to make sure that itis within the desired ranges.

At decision step 3076, it is determined whether the change in positionof head section 38 occurred in the upward or downward direction. Thisdetermination is derived from the comparison of the current head angleto the previous head angle. As shown in Table 5, the ranges of valuesindicating a change in head elevation overlap, in order to take intoconsideration hysteresis in the head angle evaluation.

For example, head section 38 will be considered to have moved fromregion zero to region 1 if a potentiometer value of about 52 is receivedby process 3070 (corresponding to a head angle of 1-10 degrees).However, once head section 38 is in region 1, it will not be consideredto have moved back to region zero unless a potentiometer reading outsidethe specified range for region 1, e.g., approximately 40 or less, isreceived.

If a change in position occurs in the downward direction, i.e., headsection 38 is lowered, then at step 3078 the inflation pressure of seatsection air zone 2304 is decreased according to the size of the patientand the current head angle. The desired pressure range is determined byreference to a look-up table stored in memory 3010. Table 4 above is anexample of such a table.

If a change in position occurs in the upward direction, i.e., headsection 38 is elevated, then at step 3080 the inflation pressure of seatsection air zone 2304 is increased. First, a “seat boost” is applied toseat section air zone 2304, meaning that seat section air zone 2304 isinitially over-inflated for a brief period of time to compensate for theabove-mentioned weight shift. Examples of the initial “seat boost”pressures are shown in Table 2 above. In the illustrated embodiment, theperiod of time for the seat boost is about 15 seconds. After the seatboost period expires, process 3070 adjusts the pressure of seat sectionbladders 2304 to the desired level based on patient size and head angle,as determined by the look-up table mentioned above.

Second Illustrative Embodiment Mattress Assembly

A second illustrative embodiment modular mattress assembly 4014 of thepresent invention is configured to be supported by deck 26′, as shown inFIG. 129, of the illustrative patient support 10′ of FIG. 57. Referringnow to FIGS. 130 and 131, the mattress assembly 4014 includes first andsecond sides 4017 a and 4017 b extending substantially parallel to alongitudinal center axis 4019 between head and foot ends 4018 a and 4018b. The modular mattress assembly 4014 includes an outer cover 2102having a bottom cover portion 2104 and a top cover portion 2106 (FIG.146) configured to encapsulate a plurality of internal componentsincluding a foam receiving base 4208. The receiving base 4208 includes afoam foot section 4210 and a foam body section 4212 coupled to the footsection 4210 illustratively by a foot section securing substrate 4340(FIG. 138). Component mounting substrates 4214, 4216 are coupled to thefoot section 4210 and the body section 4212, respectively, of the base4208. A foot or heel bladder assembly 4215 is coupled to the mountingsubstrate 4214. A foam filler or panel 4218 is supported above themounting substrate 4216 and is received within the base 4208. A turnassist bladder assembly 4220 is received above the foam filler 4218 andis coupled to the mounting substrate 4216. An upper bladder assembly4222 is received above the turn assist bladder assembly 4220 and islikewise coupled to the mounting substrate 4216. A fire sock or barrier2124 is configured to surround the receiving base 4208, including thefoot section 4210 and the body section 4212, the mounting substrates4214 and 4216, the heel bladder assembly 4215, the foam filler 4218, theturn assist bladder assembly 4220, and the upper bladder assembly 4222.A shear cover 2125 is configured to be received over the fire barrier2124. The top cover portion 2106 is configured to be coupled to thebottom cover portion 2104 to receive the other mattress components andto define the outer cover 2102. A mattress fluid connector 4068 iscoupled to the bottom cover portion 2104 and is configured to providefluid communication between a manifold 4063, which is coupled to a pump4064, and the mattress 4014.

Mattress Foot Section Assembly

As detailed above with respect to leg section 42 of deck 26, the legsection 42′ of the deck 26′ is likewise extendable and retractable.FIGS. 132 and 133 further illustrate the foot section 4210 of themattress 4014 which is configured to extend and retract with themovement of the adjustable leg section 42′ of the articulating deck 26′.The foot section 4210 includes a base portion 4228 and a pair ofopposing flange portions 4230 and 4232 supported above the base portion4228. The base portion 4228 includes angled sidewalls 4234 and 4236which are configured to conform to the angled sidewalls 291, 300 of thedeck 26′. The flange portions 4230 and 4232 are configured to extend outbeyond the angled sidewalls 291, 300 of the deck 26′. Illustratively,the foot section 4210 is made of a resilient polyurethane foam.

The foot section 4210 is perforated to facilitate its longitudinalextension and retraction. More particularly, the foot section 4210 isformed to include a plurality of apertures, illustratively transverselyextending slots 4238 extending in a generally vertical direction throughthe base portion 4228 and the flange portions 4230 and 4232, tofacilitate compressibility of the foot section 4210 in response to theretraction of the leg section 42′ of the deck 26′. More particularly,the plurality of slots 4238 are arranged in a plurality of laterallyextending rows 4240 wherein the individual slots 4238 of each row 4240are laterally offset from those slots 4238 of longitudinally adjacentrows 4240. It may be readily appreciated, each slot 4238 widens toaccommodate the extension of the leg section 42′ and narrows toaccommodate the retraction of the leg section 42′ of the deck 26′.

While in the illustrative embodiment a plurality of discrete laterallyand longitudinally spaced transverse slots 4238 are illustrated tofacilitate retraction and extension of the foot section 4210, it shouldbe appreciated that other structures may be readily substitutedtherefor. More particularly, the foot section 4210 may be formed toinclude serpentine channels or a plurality of slots extendingsubstantially the full width of the foot section 4210 between opposingside edges of the flange portions 4230 and 4232.

A foot section mounting plate 4242 is secured to a lower surface 4244 ofthe foot section 4210, illustratively through an adhesive tape 4245. Asdescribed in greater detail below, the foot section mounting plate 4242provides a securing platform for a foot section anchor 4246 whichcouples the foot section 4210 to the leg section 42′ of the deck 26′ tofacilitate movement in cooperation therewith.

The foot section 4210 further includes a receiving recess 4248 extendingdownwardly from an upper surface 4250 of the base portion 4228 at a footend 4252 thereof. The heel bladder assembly 4215 defines a heel pressurerelief zone 4254 and is coupled to the foot mounting substrate 4214 andis received within the recess 4248. Opposing first and second ends ofthe foot mounting substrate 4214 are coupled to a pair of footattachment straps 4256. The attachment straps 4256 each have a centermounting aperture 4257 coupled to the foot section mounting member 4242through a conventional fastener, such as a button 4258. Similarly,opposing ends of the foot attachment straps 4256 including mountingapertures 4259 which are secured to the opposing ends of the footmounting substrate 4214 through conventional fasteners, such as buttons4258 (FIGS. 133 and 136).

Heel Bladder Assembly

As noted above, the heel bladder assembly 4215 is supported within therecess 4248 and is coupled to the foot mounting substrate 4214. Asillustrated in FIGS. 132, 134 and 135, the heel bladder assembly 4215includes a total of four laterally extending air bladders 4264. However,it should be appreciated that any number of bladders 4264 may beprovided in the foot section 4210 depending upon the area required forthe heel pressure relief zone 4254. Each bladder 4264 includes a fluidchamber illustratively defined by a sheet 4265 which is generally foldedin half to form a tubular member, wherein the open side edges and bottomedges are sealed through conventional means, such as radio-frequency(RF) welding, to form the fluid chamber. The bladders 4264 areillustratively formed of a polymer material, such as a polyolefin. Theplurality of air bladders 4264 are fluidly connected. More particularly,the first bladder 4264 a is fluidly connected to the second air bladder4264 b through a conventional U-shaped fluid connector 4266 a, thesecond bladder 4264 b is fluidly connected to the third bladder 4264 cthrough a conventional U-shaped fluid connector 4266 b, and the thirdbladder 4264 c is fluidly connected to the fourth bladder 4264 d througha conventional U-shaped fluid connector 4266 c (FIGS. 130 and 134).

Referring further to FIGS. 130 and 133-135, a plurality of outer andinner fasteners 4268 and 4270, illustratively snaps, are secured to thefoot mounting substrate 4214 proximate opposing side edges thereof. Thefoot mounting substrate 4214 is formed from a flexible sheet material,such as polyurethane coated twill. Opposing ends of each bladder 4264include an upper fastener 4272 and a lower fastener 4274, illustrativelysnaps, which cooperate with the outer fastener 4268 and the innerfastener 4270 of the foot mounting substrate 4255.

A foot fill tube 4276 is fluidly connected to the first bladder 4264 awhile a foot sensor tube 4278 is fluidly connected to the fourth fluidbladder 4264 d. As illustrated in FIGS. 134 and 135, the foot fill tube4276 and the foot sensor tube 4278 extend from the heel bladder assembly4215 toward the body section 4212 of the receiving base 4208 and fromproximate the first side 4017 a of the mattress 4014 to proximate thesecond side 4017 b of the mattress 4014. In other words, respectiveportions of the tubes 4276 and 4278 extend diagonally below the lowersurface 4244 of the foot section 4210 of the base 4208 in order toaccommodate extension and retraction thereof without kinking or pulling.The tubes 4276 and 4278 next extend toward the head end 4018 a of themattress 4014 by passing between the mounting substrate 4216 and thebody section 4212 of base 4208 proximate second side 4017 b of themattress 4014. The tubes 4276 and 4278 pass through a slit 4275 formedin the mounting substrate 4216 and pass between the mounting substrate4216 and the turn assist bladder assembly 4220 to the mattress connector4068.

The tubes 4276 and 4278 may be coupled to the foot section mountingmember 4242 through a conventional cable tie (not shown). Furtherretention of the tubes 4276 and 4278 to the mounting substrate 4216 maybe provided by a securing loop 4338 coupled to the mounting substrate4216.

The heel bladder assembly 4215 is configured to provide heel pressurerelief by reducing the level of raised pressure between the patient'sfoot and the mattress. More particularly, the heel bladder assembly 4215provides for a region of reduced pressure below the patient's heels. Thefoot section 4210 includes a calf portion 4279 which supports theportion of the patient's weight that would otherwise be supported by thepatient's heel and thus reduces the overall interface pressure betweenthe patient's heel and the mattress 4014. It is envisioned that the calfportion 4279 of the mattress 4014 may include a transition zone wherethe material stiffness of the foot section 4210 decreases in alongitudinal direction extending generally from head end 4018 a to thefoot end 4018 b of mattress 4014.

Mattress Body Section Assembly

The body section 4212 of the receiving base 4208 is further illustratedin FIGS. 138 and 140 as including a bottom layer 4280 secured tolongitudinally extending first and second sidewalls or bolsters 4281 and4282. Likewise, an end wall or bolster 4283 is coupled to the first andsecond sidewalls 4281 and 4282 and the bottom layer 4280. As such, thebody section 4212 defines a longitudinally extending channel or bucket4284 configured to receive various components of the mattress 4014. Asdescribed in greater detail below, a fluid connector recess 4285 isformed near the head end 4286 of the body section 4212 and is configuredto receive the mattress fluid connector 4068.

The sidewalls 4281 and 4282 each include an angled or inclined portion4288 coupled to a flange portion 4290. The angled portions 4288 areconfigured to conform to the angled sidewalls 260 and 262 of the deck26′, while the flange portions 4290 are configured to extend above andout beyond the sidewalls 260 and 262 of the deck 26′. The body section4212 of the receiving base 4208 includes a head portion 4292 and a seatportion 4294 separated by a laterally extending slit 4296 (FIG. 130).Opposing ends of the slit 4296 include stress relief apertures (notshown) formed within the sidewalls 4281 and 4282. As described ingreater detail below, the slit 4296 facilitates relative movement of thehead and seat portions 4292 and 4294 of the body section 4212 duringarticulation of the head and seat sections 4038 and 4040 of the deck26′.

Mattress Mounting Substrate

With reference to FIGS. 130, 137 and 138, the mounting substrate 4216 isreceived within channel 4284 defined by the body section 4212 of thereceiving base 4208. Opposing first and second end portions 4302 and4304 of the mounting substrate 4216 are coupled to first and secondupper mounting plates 4306 and 4308. In turn, the upper mounting plates4306 and 4308 are secured to an upper surface of the receiving base4208, illustratively through double sided adhesive tape 4307 and 4309,respectively. A plurality of fasteners, illustratively buttons 4312 aresecured to the upper mounting plates 4306 and 4308. The buttons 4312 arereleasably received within a plurality of substrate securing apertures4314 formed within the mounting substrate 4216, thereby connecting themounting substrate 4216 to the receiving base 4208 through the uppermounting plates 4306 and 4308. A head section mounting plate 4316 issecured to a lower surface of the receiving base 4208, illustrativelythrough means of a double sided adhesive tape 4318. As detailed below,the head section mounting plate 4316 provides a coupling platform for ahead anchor strip 4320 which secures the body section 4212 of thereceiving base 4208 to the head section 4038 of the deck 26′.

The mounting substrate 4216 includes a base portion 4322 and first andsecond mounting portions 4324 and 4326 extending along opposinglongitudinal side edges of the base portion 4322. Each mounting portion4324 and 4326 includes a outer mounting member 4328 and an innermounting member 4330 hingedly connected to the outer mounting member4328 through a hinge 4329. The mounting members 4328 and 4330 include aplurality of longitudinally spaced outer and inner fasteners 4332 and4334, illustratively snaps, configured to couple to correspondingfasteners of the upper bladder assembly 4222 as detailed below. Aplurality of turn assist bladder assembly securing apertures 4336 areformed proximate opposing longitudinally extending side edges of themounting substrate 4216. As detailed below, the apertures 4336 areconfigured to receive fasteners, such as buttons 4337 for securing theturn assist bladder assembly 4220 to the mounting substrate 4216. Firstand second securing loops 4338 and 4339 are coupled to the base portion4322 and are configured to receive various fluid tubes for retentiontherein.

Foot Section Securing Substrate

With further reference to FIG. 138, the foot section 4210 may be securedto the receiving base 4208 through the use of a foot section securingsubstrate 4340. The foot section securing substrate 4340 includes afirst portion 4342 secured to the upper mounting plate 4308 of the seatportion of the receiving base 4208 and a second portion 4344 secured tolower surface 4277 of the foot section 4210. More particularly, thefirst portion 4342 of the foot section securing substrate 4340 includesa plurality of mounting apertures configured to receive fasteners, suchas buttons 4312. The buttons 4312 are secured to the upper mountingplate 4308, which is coupled to the upper surface of receiving base 4208as detailed above. The second portion 4344 of the securing substrate4340 is directly coupled to a lower surface of the foot section 4210,illustratively through an adhesive. The second portion 4344 includes aplurality of transverse slots 4350 configured to be received in paralleldisposition with the transverse slots 4238 formed within the footsection 4210.

Illustratively, the foot section securing substrate 4340 is formed froma flexible sheet material, such as pack cloth urethane coated twill. Asa flexible sheet material, the foot section securing substrate 4340 mayfollow a serpentine path from a horizontal first plane of the bottomlayer 4280 of the receiving base 4208 and vertically down around a footend edge 4352 of the receiving base 4208, and back along a horizontalplane of the lower surface 4277 of the foot section 4210.

Foam Filler

The foam filler or panel 4218 is received within the channel 4284defined by the sidewalls 4281 and 4282 of the body section 4212 of thereceiving base 4208. Illustratively, the filler 4218 is made ofpolyurethane foam having an indention force deflection (IFD) of betweenapproximately 23 pounds to approximately 29 pounds. IFD is commonlydefined in the art as the amount of force necessary to indent an 8 inchdisc plate 25 percent into the foam of a 4 inch thick sample 15 inchesby 15 inches square. Further illustratively, the filler 4218 includessidewalls 4354 and 4355 which are angled to conform with the angledwalls 4281 and 4282 of the receiving base 4208. A fastener,illustratively a loop portion 4356 of a conventional hook and loopfastener, is secured to a lower surface of the foam filler 4218 and isconfigured to couple with a mating hook portion 4357 secured to an uppersurface of the receiving base 4208. A clearance opening 4359 is formedwithin the mounting substrate 4216 to allow for coupling of the fastenerportions 4356 and 4357.

Turn Assist Bladder Assembly

Referring to FIGS. 130 and 139-141, the turn assist bladder assembly4220 is positioned above the foam filler 4218 and includes a first, orright, inflatable turn assist bladder 4358 and a second, or left,inflatable turn assist bladder 4360. As described in greater detailherein, each of the right and left turn assist bladders 4358 and 4360are selectively and individually inflatable to assist in the turning ofa patient supported on the mattress 4014. FIG. 140 illustrates both theright and left turn assist bladders 4358 and 4360 in deflated positions,while FIG. 141 illustrates the left turn assist bladder 4360 in adeflated position and the right turn assist bladder 4358 in an inflatedposition.

Each of the turn assist bladders 4358 and 4360 include an upper layer4362 and a lower layer 4364 coupled to the upper layer 4362. Right andleft turn assist fill tubes 4366 and 4368 are configured to be coupledto the manifold assembly 4063 which, in turn, is coupled to the pump4064 that provides pressurized air to inflate the chamber definedbetween the upper and lower layers 4362 and 4364 of the turn assistbladders 4358 and 4360, respectively. Right and left turn assist sensortubes 4370 and 4372 are also provided in fluid communication with thechamber defined between the upper and lower layers 4362 and 4364 of theturn assist bladders 4358 and 4360, respectively. The sensor tubes 4370and 4372 are likewise configured to be placed in fluid communicationwith the manifold assembly 4063 which, in turn, is in fluidcommunication with a pressure sensor 566 for detecting the pressure ofair within the bladders 4358 and 4360. The fill tubes 4366 and 4368extend generally in a longitudinal direction from proximate the head endof the respective bladders 4358 and 4360 to the mattress connector 4068proximate the head end of the receiving base 4208. The sensor tubes 4370and 4372 extend from a foot end of the respective bladders 4358 and 4360laterally to proximate first side 4017 a of the mattress 4014 andintermediate the turn assist bladder assembly 4220 and the mountingsubstrate 4216. The sensor tubes 4370 and 4372 continue through securingloop 4339 and are coupled to mattress connector 4068.

Right and left mounting flanges 4376 and 4378 extend in directionsoutwardly from opposing edges of the right and left turn assist bladders4358 and 4360, respectively. Illustratively the mounting flanges 4376and 4378 are secured to the lower layers 4364 of the bladders 4358 and4360 through radio frequency (RF) welding. The mounting flanges 4376 and4378 include a plurality of mounting apertures 4380 proximate theirrespective side edges 4382 and 4384. Releasable fasteners, such as thebuttons 4337, are received within the apertures 4380 of the mountingflanges 4376 and 4378, and likewise are received within the apertures4336 of the mounting substrate 4216. As such, the turn assist bladderassembly 4220 is secured to the mounting substrate 4216. The turn assistbladder assembly 4220 may be made from polyurethane film.

Upper Bladder Assembly

The upper bladder assembly 4222 is positioned above the turn assistbladder assembly 4220, such that the turn assist bladder assembly 4220is sandwiched between the foam filler 4218 and the upper bladderassembly 4222 (FIGS. 130, 140 and 141). Referring to FIGS. 142 and 143,the upper bladder assembly 4222 defines a head section or air zone 4390and a seat section or air zone 4392, wherein each zone 4390 and 4392includes a respective bladder assembly 4394 and 4396. Both bladderassemblies 4394 and 4396 include a plurality of laterally extendingbladders 4398 and 4400, respectively. Each bladder 4398, 4400 is movableindependently from every other bladder 4398, 4400 and is separatelycoupled to the mounting substrate 4216. In the illustrated embodiment, atotal of nine (9) bladders 4398 a-4398 i define the head section 4390,while a total of six (6) bladders 4400 a-4400 f define the seat section4392. However, it should be appreciated that any number of bladders4398, 4400 may be included within the various sections or zones 4390,4392 of the mattress 4014.

Each bladder 4398, 4400 is substantially identical to the bladders 4264of the heel bladder assembly 4215. As such, similar or identicalreference numbers are utilized to indicate similar or identicalcomponents in bladders 4264, 4398 and 4400. Bladders 4398, 4400 eachincludes upper and lower inflatable center portions 4402 and 4404 andopposing upper inflatable end portions 4406 and 4408. The upperinflatable center portion 4404 is separated from the end portions 4406and 4408 by hinge portions 4403 and 4405. The end portions 4406 and 4408define first and second notches or spaces 4407 and 4409 which areconfigured to provide clearance for movement of the bladder 4398 aboutthe hinge portions 4403 and 4405. Webs 4415 and 4417 are located in thenotches 4407 and 4409 and connect the lower center portion 4404 to theend portions 4406 and 4408, respectively.

The bladders 4398, 4400 each include an upper fastener 4272 and a lowerfastener 4274, illustratively snaps, configured to cooperate with theouter and inner fasteners 4332 and 4334 of the mounting substrate 4216.As illustrated in FIGS. 17 and 18, the inner mounting member 4330 isconfigured to move vertically relative to the outer mounting member 4328through hinge 4329, thereby facilitating movement of the end portions4406 and 4408 of the bladders 4398 relative to the center portions 4402and 4404 of the bladders 4398. More particularly, the inner mountingmember 4330 is configured to pivot relative to the outer mounting member4328 about the hinge 4329. This coupling structure permits the endportions 4406 and 4408 of the bladders 4398 to hinge during operation ofthe turn assist bladder assembly 4220 and prevent undesirable raising ofthe end portions 4406 and 4408 or uncoupling from the mounting substrate4216.

Further, the couplings between the bladders 4398 of the upper bladderassembly 4220 and the mounting substrate 4216 define an upper crowningsurface 4410. More particularly, the upper surface 4410 of the bladderassembly 4220 proximate the longitudinal center axis 4019 of theassembly 4220 is positioned vertically above the upper surface 4410proximate the opposing longitudinal side edges 4412, 4413 of the bladderassembly 4220. Illustratively, the vertical distance of the crowningupper surface 4410 from the center axis 4019 to the respective sideedges 4412, 4413, as represented by reference letter “d” in FIG. 140, isapproximately 2 inches. The upper surface 4019 is arcuate as it extendsfrom the center axis 4410 to the side edges 4412, 4413.

The crowning surface 4410 is configured to facilitate lateral patienttransfer from the bed 4010 to another patient support device positionedadjacent to the bed 4010 by creating an inclined surface which providesa slight amount of gravity assistance when the caregiver is moving thepatient toward the side of the mattress 4014. Additionally, since thesurface 4410 at the side edges 4412 and 4413 is lower than proximate thecenter axis 4411, the siderails 4020 and 4022 may have a lower profileand still fulfill minimum height requirements.

FIG. 141 illustrates a right turn assist mode of operation wherein theright turn assist bladder 4358 is inflated. Since the right turn assistbladder 4358 is laterally offset from the longitudinal center axis 4019of the mattress 4014, inflation of the bladder 4358 causes side edge4413 of the upper bladder assembly 4222 to raise above the opposing sideedge 4412. The hinge portions 4403 and 4405 between the end portions4406 and 4408 and the center portion 4407 of the bladders 4398, 4400 ofthe upper bladder assembly 4222 permit the mattress 4014 tosubstantially conform to the shape resulting from the inflation ofeither turn assist bladder 4358, 4360. In an illustrative embodiment,upon inflation of one of the turn assist bladders 4358 and 4360, apatient supported on the mattress 4014 is rotated by an angle ofapproximately 20 degrees from horizontal. Upon completion of the turnassist, the control system 44 causes the inflated turn assist bladder4358, 4360 to vent to atmosphere. Simultaneously, the upper bladderassembly 4222 is instructed by the central system 44 to inflate to amaximum pressure, also known as a max inflate mode of operation. Sincethe turn assist bladder assembly 4220 is sandwiched intermediate theupper bladder assembly 4222 and the filler 4218, inflation of the upperbladder assembly 4222 facilitates the rapid venting of air within theturn assist bladders 4358 and 4360 to atmosphere.

A pair of seat attachment straps 4425 are configured to couple togetherselected air bladders 4440 of the seat bladder assembly 4396,illustratively bladders 4400 a-4400 c. The straps 4425 illustrativelywrap around the bladders 4440 a-4440 c and have ends coupled togetherwith conventional fasteners, such as buttons 4427.

Fluid Tube Routing

A head section fill tube 4414 and a head section sensor tube 4416 arecoupled to the head section 4390. More particularly, the fill tube 4414is fluidly coupled to the air bladder 4398 e proximate the longitudinalcenter of the head section 4390, and the sensor tube 4416 is fluidlycoupled to the air bladder 4398 i proximate the seat section 4392. Boththe fill tube 4414 and the sensor tube 4416 travel from respectivebladders 4398 e and 4398 i in a generally longitudinal direction, to themattress connector 4068 at the head end of the receiving base 4208,intermediate the bladders 4398 and the turn assist bladder assembly4220. Both tubes 4414 and 4416 are received within securing loop 4338. Ahead section connection assembly 4418 fluidly connects each of thebladders 4398 and illustratively comprises a plurality of conventionalT-shaped fluid connectors 4420 and L-shaped fluid connectors 4422.

A seat section fill tube 4424 and a seat section sensor tube 4426 arecoupled to the seat section 4392. More particularly, the fill tube 4424is fluidly coupled to a seat section connection assembly 4428 which, inturn, is fluidly coupled to each air bladder 4400 of the seat bladderassembly 4396. The seat section connection assembly 4428 illustrativelycomprises a plurality of T-shaped fluid connectors 4420 and an L-shapedfluid connector 4422. The sensor tube 4426 is fluidly coupled to airbladder 4400 d located proximate the longitudinal center of the seatsection 4392. Both the fill tube 4424 and the sensor tube 4426 travelfrom the seat bladder assembly 4396 in a generally longitudinaldirection to the mattress connector 4068 at the head end of thereceiving base 4208. The fill tube 4424 travels along sidewall 4282 ofthe receiving base 4208 intermediate the upper bladder assembly 4222 andthe turn assist bladder assembly 4220, and is received within securingloop 4339 of the mounting substrate 4216. Similarly, the sensor tube4426 travels along sidewall 4281 of the receiving base 4208 intermediatethe upper bladder assembly 4222 and the turn assist bladder assembly4220, and is received within securing loop 4338 of the mountingsubstrate 4216.

Fire Barrier

Referring again to FIG. 130, the fire barrier 2124 receives the internalmattress components including the receiving base 4208, the mountingsubstrates 4214 and 4216, the foam filler 4218, the turn assist bladderassembly 4220, the upper bladder assembly 4222, and the heel bladderassembly 4215. The fire barrier 2124 includes an open end 2356configured to permit the fire barrier 2124 to slide over the othermattress components. Upon assembly, the open end 2356 of the firebarrier 2124 is closed utilizing conventional means, such as fasteners.The fire barrier 2124 may be made from a conventional fire-resistantmesh material, such as a fiberglass knit.

Shear Cover

The shear cover 2125 is configured to fit over the above-identifiedmattress components as received within the fire barrier 2124. The shearcover 2125 is configured to be located between the fire barrier 2124 andthe outer cover 2102 to permit the top cover portion 2106 to slideeasily over the fire barrier 2124 and move relative to the otherinternal mattress components, thereby reducing shear forces between thepatient's body and the mattress 4014 and reducing the likelihood ofsacral breakdown.

The shear cover 2125 is formed from a material having a low coefficientof friction so that the mattress outer cover 2102 can slide relative tothe other mattress components. As the mattress 4014 is articulated or asthe patient moves, the shear cover 2125 minimizes shear forces actingbetween the mattress top cover portion 2106 and the patient's body. Theshear cover 2125 may be made from a woven nylon or parachute material.Illustratively, the shear cover 2125 is made from a polyurethanematerial such as Deerfield urethane PT611OS having a thickness ofapproximately 0.002 inches. The polyurethane material provides aninexpensive shear material which reduces shear forces applied to thepatient's body situated on the mattress 4014.

Additional details of the shear cover 2125 and the top cover portion2106 are described above.

Outer Cover

Referring now to FIGS. 57 and 146, the bottom cover portion 2104includes a bottom wall 2366 and a sidewall 2368. The sidewall 2368 isillustratively formed from a ticking material and is coupled to thesidewall 2364 of the top cover portion 2106, illustratively through RFwelding. Illustratively, the bottom wall 2366 of the bottom coverportion 2104 is formed from a polyurethane coated twill material forenhanced wear resistance and to protect other components of the mattress4014 from contamination. The bottom wall 2366 includes an access panel2370 defined by a zipper 2372. The access panel 2370 is utilized duringassembly of the mattress 4014 and further facilitates removal of thereplacement of the modular components of the mattress 4014.Illustratively, the zipper 2372 is RF welded to the bottom wall 2366. Inan alternative embodiment of the invention, the zipper 2372 may beutilized to couple the sidewall 2368 of the bottom cover portion 2104 tothe sidewall 2364 of the top cover portion 2106.

With further reference to FIG. 146, the bottom cover portion 2104includes a stress relief zone 2374 of extra material, which isillustratively pleated, to accommodate movement of the head section 4038of the deck 26′ relative to the seat section 4040 of the deck 26′. Moreparticularly, as the head section 4038 is elevated relative to the seatsection 4040, the head portion 4292 of the receiving base 4208 movesrelative to the seat portion 4294 of the receiving base 4208. The slit4296, and connected stress relief apertures, reduce the stress appliedto the receiving base 4208 during this movement. Likewise, the stressrelief zone 2374 of the bottom cover portion 2104 reduces stress withinthe outer cover 2102 of the mattress 4014. As the mattress 4014 bends tofollow the contour of the deck 26′, the extra material within the stressrelief zone 2374 accounts for the increased distance between the headportion 4292 and the seat portion 4294 proximate the bottom coverportion 2104.

Mattress Anchors

With further reference to FIGS. 7130, 132, 133, and 146, the footsection anchor 4246 is coupled to the foot section 4210 of the receivingbase 4208 below the bottom cover portion 2104, illustratively throughfasteners 4247 threadably received within the foot section mountingplate 4242. Likewise, the head section anchor 4320 is secured to thehead portion 4292 of the receiving base 4208 below the bottom coverportion 2104, illustratively through fasteners 4247 threadably receivedwithin the head section mounting plate 4316. The foot section anchor4246 and the head section anchor 4320, each illustratively comprises aresilient tab or strip 4429 having opposing first and second ends 4430and 4431 which may be flexed away from the bottom cover portion 2104 ofthe mattress 4014, and placed under the respective retaining brackets4082 and 4080 formed within the leg section 42′ and the head section 38′of the deck 26′, respectively, as illustrated in FIG. 129.

Manifold Assembly and Mattress Connectors

Referring now to FIGS. 130, 138 and 148-150, the mattress fluidconnector 4068 is secured to the bottom cover portion 2104 and isreceived within the connector recess 4285 formed within the receivingbase 4208. The mattress connector 4068 includes a plurality of barbedfittings 4432 and 4434, each of which is sealingly received withinflexible tubing illustratively connected to one of the heel bladderassembly 4215, the right turn assist bladder 4358, the left turn assistbladder 4360, the head section 4390 of the upper bladder assembly 4222,and the seat section 4392 of the upper bladder assembly 4222. Moreparticularly, fitting 4432 a is fluidly coupled to right turn assistfill tube 4366, fitting 4432 b is fluidly coupled to left turn assistfill tube 4368, fitting 4432 c is fluidly coupled to foot section filltube 4276, fitting 4432 d is fluidly coupled to seat section fill tube4424, and fitting 4432 e is fluidly coupled to head section fill tube4414. In a similar fashion, fitting 4434 a is fluidly coupled to thefoot section sensor tube 4278, fitting 4434 b is fluidly coupled to thehead section sensor tube 4416, fitting 4434 c is fluidly coupled to theseat section sensor tube 4426, fitting 4434 d is fluidly coupled to theleft turn assist sensor tube 4372, and fitting 4434 e is fluidly coupledto the right turn assist sensor tube 4370.

The pneumatic connections to the manifold assembly 4063 of the presentinvention is further illustrated in FIG. 147. The manifold assembly 4063is configured to provide fluid communication between the pump 4064 andthe air mattress 4014. The manifold assembly 4063 is configured tocontrol the supply of air to and the exhaust of air from the controlledair zones of the mattress 4014. Air is supplied to the manifold 4063 bythe pump 4064, while air is exhausted to atmosphere 2405 through themanifold 4063. More particularly, the manifold 4063 controls airpressure within the right turn assist bladder 4358, the left turn assistbladder 4360, the head zone of the upper bladder assembly 4222 and theseat zone of the upper bladder assembly 4222. While in the followingdescription, a single manifold 4063 is utilized, it should beappreciated that in other embodiments multiple manifolds may besubstituted therefore.

With further reference now to FIG. 147, air supplied from the pump 4064passes to the manifold 4063 though a supply tube. Once entering themanifold 4063, the supplied air is routed through to various valveassemblies in the manner detailed above with respect to valve assemblies2406.

The sensing lines 4278, 4370, 4372, 4416, and 4426 from the controlledair zones of the mattress 4014 are coupled in fluid communication withthe manifold 4063. In the illustrative embodiment, each sensing line4278, 4370, 4372, 4416, and 4426 supplies air to the mattress connector4068 which, in turn, provides air to the manifold connector 4070. Theair exits the manifold connector 4070 through pressure sensing tubes2440. Each tube 2440 is coupled to a pressure sensor 566 supported on avalve controller circuit board 2444. The circuit board 2444 is incommunication with the control system 44 and as such, provides signalsto the control system 44 indicative of pressure within the variouscontrolled air zones of the mattress 4014. In an alternative embodiment,each sensing line 4278, 4370, 4372, 4416, and 4426 supplies air whichpasses through fluid sensing ports (not shown) formed within themanifold 4063 and then exits through pressure sensing tubes 2440.

The mattress connector 4068 is configured to couple to the manifoldconnector 4070 which is in fluid communication with the manifold 4063.The partition wall 272 coupled to the deck 26′ is positionedintermediate the manifold connector 4070 and the manifold 4063. Themanifold connector 4070 is configured to sealingly mate with themattress connector 4068. The manifold connector 4070 includes aplurality of outlets 4436, 4438 configured to sealingly receive plugs4440, 4442, respectively, of the mating mattress connector 4068. Theoutlets 4436 of the manifold connector 4070 are in fluid communicationwith the valve assemblies of the manifold 4063, while the plugs 4440 a,4440 b, 4440 c, 4440 d, and 4440 e are in fluid communication with thecontrolled air zones 4358, 4360, 4254, 4392, and 4390 of the mattress4014 through respective fittings 4432 and fill tubes 4366, 4368, 4276,4424, and 4414 in the manner detailed above. The outlets 4438 of themanifold connector are in fluid communication with the pressure sensors566 through the manifold 4063, while the plugs 4442 a, 4442 b, 4442 c,4442 d, and 4442 e are in fluid communication with the controlled airzones 4358, 4360, 4254, 4392, and 4390 of the mattress 4014 throughfittings 4434 and sensor tubes 4278, 4416, 4426, 4372, and 4370. As maybe readily appreciated, in alternative embodiments, the sensor tubes maybypass the manifold 4063 and be directly connected to the respectivepressure sensors 566.

Each of the plugs 4440 and 4442 illustratively includes a conventionalO-ring gasket 4444 to promote sealing with a mating outlet 4436 and4438. The mattress connector 4068 includes a peripheral inner flange4446 which is configured to be received within a peripheral outer flange4448 of the manifold connector 4070. Illustratively, a plurality offasteners 4450 lock the peripheral flanges 4446 and 4448 together.Illustratively, each fastener 4450 comprises a spring-biased U-shapedtab 4452 extending outwardly from the mattress connector 4068 andincluding an opening 4454 configured to be received over a locking tab4456 supported by the manifold connector 4070. A U-shaped retainingmember 4457 is supported by the manifold connector 4070 in spacedrelation to the locking tab 4456 such that the tab 4452 of the mattressconnector 4068 may be received therebetween. In the illustrativeembodiment of FIG. 148, the locking tab 4456 in an upper fastener 4450is removed to assist in the uncoupling and removal of the connectors4068 and 4070. It should be appreciated that other conventionalfasteners, such as hook and loop fasteners, clamps or staples may bereadily substituted therefor.

As described above, the manifold connector 4070 is coupled to themanifold 4063, respectively, through the partition wall 272.Conventional fasteners, such as screws 4058, may be utilized to securethe manifold connector 4070 and the manifold 4063 relative to thepartition wall 272. In one illustrative embodiment, cylindrical gasketsmay be positioned intermediate each outlet 4436, 4438 of the manifoldreceiving connector 4070 and the manifold 4063 in order to effectsealing therebetween. In a further illustrative embodiment, a gasket2502′ (FIG. 151) may be positioned intermediate the manifold connector4070 and the partition 272. Gasket 2502′ may be of a designsubstantially similar to gasket 2502 as shown in FIGS. 122 and 123.

Mattress Sensor

With reference to FIGS. 35A, 150, and 151, the connection between themattress connector 4068 and the manifold connector 4070 is detected by amattress sensor 4462. If the sensor 4462 does not detect that a mattress4014 has been connected to the control system 44 by the coupling of themattress connector 4068 to the manifold connector 4070, then the controlsystem 44 does not permit operation of the air mattress functions.

According to an illustrative embodiment, the sensor 4462 comprises aHall effect field sensor 4464 that detects the characteristics of adynamic field generated by the mattress connector 4068. Moreparticularly, a magnet 4466 is positioned within a receiving boss 4468of the mattress connector 4068 (FIG. 151). The manifold connector 4070includes an opening 4470 configured to receive the boss 4468, and themagnet 4466 received therein, when the mattress connector 4068 isfluidly coupled with the manifold connector 4070. As such, the Halleffect sensor 4464 detects the magnetic field generated by the magnet4466. Based upon the detection of the predetermined magnetic field, thesensor 4464 sends a signal indicative of the respective mattress 4014 tothe control system 44. The control system 44 then permits operation ofthe air mattress functions.

An illustrative circuitry associated with the sensor 4464 is shown inFIG. 152. The circuitry includes an op-amp 4474 coupled to the sensor4464, an open collector 4476, a transistor 4478, and a resistor 4480.The sensor 4464, the op-amp 4474, the open collector 4476, and thetransistor 4478 are coupled to ground 4482. The sensor 4464, the op-amp4474, the open collector 4476, and the resistor 4480 are illustrativelycoupled to a five volt source. The transistor 4478 and the resistor 4480are coupled to the output of the circuit. Illustratively, the resistor4480 has a value of 470 ohms, and the sensor 4464 is a Cherry MP1013Snap Fit Proximity Sensor that detects magnetic fields and is sold bythe Cherry Corporation, 3600 Sunset Avenue, Waukegan, Ill. It should beappreciated that based upon the desired control characteristics, thevalue of the resistor 4480 and the proximity sensor 4464 may be varied.

Further, the type and functionality of an air mattress 4014 connected tothe manifold connector 4070 may be associated with a predeterminedsensitivity of Hall effect sensor 4464 or strength of magnet 4466.Alternatively, multiple magnets 4466 and associated Hall effect sensors4464 may be used to distinguish between different types of mattresses4014. Upon sensing a particular type of mattress 4014, the controlsystem 44 may deactivate and/or activate selected functions. Forexample, should the control system 44 receive a signal from the mattresssensor 4462 indicating that the mattress 4014 has no turn assist bladderassembly 4220, then the left and right turn assist functionality may bedeactivated.

In a further illustrative embodiment, the presence of the fluidconnector 4068 of the mattress 4014 may be detected by the pressuresensors, illustratively pressure transducers 566, which are incommunication with the control system 44. More particularly, the controlsystem 44 can initiate a diagnostic routine or process at predeterminedintervals by supplying pressure to the outlets 4436 in the manifoldconnector 4070. Should no mattress 4014 be connected to the manifoldconnector 4070, then the pressure transducers 566 connected to thesensor outlets 4438 will measure atmospheric pressure (i.e., no backpressure). However, if a mattress 4014 is connected, then the sensoroutlets 4438, upon the application of fluid through the fill outlets4436, will measure a certain amount of back pressure. As such, throughthis diagnostic routine, the control system 44 can determine if amattress 4014 is connected to the manifold 4063, and also which outlets4436 are connected to respective air zones 4254, 4358, 4360, 4390 and4392. Again, if the control system 44, through operation of the pressuresensors 566, determines that only certain air zones 4254, 4358, 4360,4390, and 4392 are coupled to the manifold 4063, then certain functionsmay be activated and others deactivated.

It should be further noted that other mattress detection devices orsensors may be readily substituted for those detailed herein. Forexample, mechanical switches, conducting pins, and other proximitysensors may be readily substituted therefor.

Pressure Control System

As detailed above with respect to FIG. 124, control system 44 includesdynamic surface module 518. In addition to other functions, dynamicsurface module 518 includes a pressure control system 3000. As shown inFIG. 124, pressure control system 3000 includes a plurality of valvesolenoids 564, a plurality of pressure sensors or transducers 566, ananalog to digital converter 3002, a microcontroller 3004, a power supply3006 and pump 4064. Microcontroller 3004 includes memory 3010 andcentral processing unit 3012.

Pressure sensors, illustratively transducers 566, periodically sense thepressure in one or more of controlled air zones 4254, 4358, 4360, 4390,and 4392 of mattress 4014 and output a voltage proportional to theamount of pressure that is sensed. Analog-to-digital converter 3002converts the voltage to digital form and feeds the digital value tomicrocontroller 3004. Microcontroller 3004 analyzes the current pressureand determines whether the current pressure in controlled air zones4254, 4358, 4360, 4390, and 4392 is correct, too high, or too low incomparison to a desired pressure. Memory 3010 stores data,illustratively in the form of look-up tables or algorithms, which isused in this analysis. For example, the desired pressure of air zones4254, 4358, 4360, 4390, and 4392 may depend on the particular operatingmode of the system 3000 (e.g., pressure relief, max-inflate, CPR, turnassist, and post-turn assist), whether head section 4038 is elevated andthe degree of elevation, and/or the size or weight of the patient. Themicrocontroller 3004 operates valve solenoids 564 in response to thefeedback signals from pressure transducers 566 to achieve the desiredadjustments to mattress 4014. The valve solenoids 564 control the flowof air to and resulting pressure within the mattress 4014. Additionaldetails regarding the valve solenoids 564 are provided above.

Valve Sensor

With reference now to FIG. 153, a valve sensor 4484 is operably coupledto the valve solenoids 564 to determine the type of pneumatic valve 2406application or technology. More particularly, the valve sensor 4484determines the presence of either (1) a direct acting solenoid valve or(2) a pilot operated, or pilot assisted, solenoid valve. The operationalrequirements for these two types of valves differ. The direct actingsolenoid valve pulls more current from a solenoid voltage source 4486,and therefore pulse modulation of the current is employed. The pilotoperated solenoid valve requires the application and maintenance of apilot air pressure.

The determination of the particular type of valve 2406 is achieved byenergizing each connected solenoid 564 individually. When a valve 2406is actuated by the closing of a valve control relay 4488, the currentpulled by the respective solenoid 564 is measured by a currenttransducer 4490. This measurement is supplied to an analog to digitalconverter 4492 which, in turn, supplies the measurement to amicrocontroller, illustratively the microcontroller 3004 of the pressurecontrol system 3000. Alternatively, the microcontroller may beindependent of the microcontroller 3004. The microcontroller 3004compares the measurement to known operating current values which arerepresentative of the direct acting solenoid valve and the pilotoperated solenoid valve. This comparison is the basis for deciding thetype of valve 2406 (i.e. direct acting solenoid valve or pilot operatedsolenoid valve).

If the microcontroller 3004 determines that the number and types ofvalves 2406 equal a predetermined configuration, then the valves 2406are driven by the microcontroller 3004 as appropriate for those types.If the microcontroller 3004 determines that the number and types ofvalves 2406 does not equal the predetermined configuration, then anerror is reported by the microcontroller 3004. In one illustrativeembodiment, the predetermined configuration is defined such that all ofthe valves 2406 coupled to the manifold 4063 are pilot operated solenoidvalves. As such, the microcontroller 3004 queries whether all of thevalves 2406 are pilot operated solenoid valves. If so, then the valves2406 are driven by the microcontroller 3004 as appropriate for pilotoperated solenoid valves. If the valves 2406 collectively are determinednot to be of the predetermined configuration, in this illustrativeembodiment meaning that all of the valves 2406 are not pilot operatedsolenoid valves, then the microcontroller 3004 reports an error. Itshould be appreciated that the predetermined configuration may compriseall direct acting solenoid valves, all pilot operated solenoid valves,or any combination thereof.

As further illustrated in FIG. 153, a supervisor relay 4496 may bepositioned intermediate the solenoid voltage source 4486 and the currenttransducer 4490. Further, the solenoid 564 is coupled to ground 4498through the valve control relay 4488.

The valve sensor 4484 permits the utilization of different predeterminedconfigurations of valves 2406 in different patient supports. Moreparticularly, the configuration of valves 2406 may be varied fordifferent types or model years of patient supports in order tofacilitate cost effectiveness and to take advantage of technologicaldevelopments in valve design. For example, in a first patient support,all pilot operated valves may be utilized and the predeterminedconfiguration stored in the microcontroller 3004 reflects thissituation. However, in a later second patient support, all direct actingsolenoid valves may be utilized. As such, the microcontroller 3004 maybe modified or re-programmed to detect this new predeterminedconfiguration.

Mattress Pressure Determination

As detailed herein, the various modes of operation include a pressurerelief mode, which is a standard operating mode of the respective airzones for providing pressure relief to the body of the patient. The maxinflate mode of operation is the operating mode for providing maximuminflation of the respective air zones. The CPR mode of operation is theoperating mode for providing a firm pressure in the respective air zonesfor assisting in the delivery of CPR to the patient. The turn assistmode of operation is the operating mode for providing pressure in therespective air zones for assisting in the left or right turning orrotation of the patient. Finally, the post-turn assist mode of operationis the operating mode for providing pressure in the respective air zonesfor assisting in the deflation of the turn assist bladders.

Tables 6-9 illustrating examples of desired pressures of air zones 4254,4358, 4360, 4390, and 4392 based on the air system operating mode,patient weight, and, for seat air zone 4392, head section elevation, areprovided as follows:

TABLE 6* HEAD SECTION Head Section Pressure (in H₂O) MODE (Pressure_Headrange) Pressure Relief$\left\lbrack {\left( {\frac{Patient\_ Weight}{100} + 1} \right) \times 3} \right\rbrack \pm 1$Max Inflate 25.0–29.0 CPR 20.0–30.0 Turn Assist$\left\lbrack {\left( {\frac{Patient\_ Weight}{100} + 1} \right) \times 3} \right\rbrack \pm 1$Post-Turn Assist 25.0–29.0 *Minimum Calculated: 65 lbs.; MaximumCalculated: 350 lbs.; Weight used for greater than 350 lbs.; 400 lbs.;Default Weight incase of error condition: 200 lbs.

TABLE 7 SEAT SECTION Seat Section Pressure (in H₂O) MODE (Pressure_Seatrange) Pressure Relief$\left\lbrack {\left( {\frac{Patient\_ Weight}{50} + 4} \right) \times \left( {\frac{Head\_ Elevation}{60} + 1} \right)} \right\rbrack \pm 1$Max Inflate 25.0–29.0 CPR 20.0–30.0 Turn Assist$\left\lbrack {\left( {\frac{Patient\_ Weight}{50} + 4} \right) \times \left( {\frac{Head\_ Elevation}{60} + 1} \right)} \right\rbrack \pm 1$Post-Turn Assist 25.0–29.0

TABLE 8 TURN ASSIST BLADDER ASSEMBLY Turn Assist Pressure (in H₂O) MODE(Pressure_TA range) Pressure Relief 0–2.0 Max Inflate 0–2.0 CPR 0–2.0Turn Assist 0–2.0 (Inactive Bladder) Turn Assist(Active Bladder)$\left( {\frac{Patient\_ Weight}{25} + 10} \right) \pm 5$ Post-TurnAssist 0–2.0

TABLE 9 HEEL PRESSURE RELIEF MEMBER Heel Pressure (in H₂O) MODE(Pressure_Heel range) Pressure Relief$\left( {\frac{Patient\_ Weight}{200} + 1} \right) \pm 0.5$ Max Inflate$\left( {\frac{Patient\_ Weight}{200} + 1} \right) \pm 0.5$ CPR — TurnAssist — Post Turn Assist —

With reference now to FIG. 154, an illustrative process 4710 ofoperation of the dynamic surface module 518 incorporating the mattresssensor 4462 begins at block 4712 with the operator or caregiverdepressing appropriate keys or buttons on the one of the controllers 50,52, 54 to deactivate or turn off the air pressure control system 3000.For example, in one embodiment, the operator simultaneously depressesthe “Pressure Relief” button 1628 and the “Max Inflate” button 1622 onthe controller 54 for a minimum of five (5) seconds in order to causethe pressure control system 3000 to deactivate or enter into an OFFmode. By deactivating the pressure control system 3000, continuousalarms or error messages for alerting the operator of the absence of anair mattress 4014 coupling are eliminated. In other words, if thepressure control system 3000 is active or in an ON mode when the airmattress 4014 is uncoupled from the control system 44 of the bed 4010,then the mattress sensor 4462 detects the absence of the air mattress4014 and controller 3004 causes an error code to display on panel 1242of the controller 54 and causes the activation of an audible alarm for apreset time period.

Next, as indicated at block 4714, the pressures in the head, seat, rightturn assist and left turn assist zones 4390, 4392, 4360 and 4362 are notregulated by the pressure control system 3000. Further, all air modeindicators 1518 on the controller 54 are deactivated or off. At block4716, the controller 3004 queries whether a mode button 1622, 1624,1626, 1628 for operation of the pressure control system 3000, has beenselected on the controller 54. If not, then the process returns to block4714. If a mode button 1622, 1624, 1626, 1628 has been selected, thenthe process continues to decision block 4718, where the controller 3004determines if the mattress sensor 4462 detects a mattress 4014.

If at block 4718, the mattress sensor 4462 does not detect a coupledmattress 4014, then the controller 3004 at block 4720 flashes selectedmode indicators 1518 on the controller 54 and also sounds an audiblealarm for a selected time period. The process then returns to block4714. If at block 4718, the mattress sensor 4462 detects a coupledmattress 4014, then the process continues to block 4722 when thepressure controller 3000 enters or initiates the selected mode ofoperation.

As such, it may be appreciated that the mattress sensor 4462 of thepresent invention provides the operator with the flexibility ofutilizing the bed 10′ with a dynamic air mattress 4014 or some othersupport surface, such as a static foam mattress. If the bed 10′ is to beused with a static foam mattress, for example, then the mattress sensor4462 signals the controller 3004 which, in turn, cannot be activated bythe operator. The pressure control system 3000 remains in an inactive orOFF mode, thereby locking out an operator from activating or turning ONthe pressure control system 3000 and attempting to use the system on afoam mattress.

The controller 3004 of pressure control system 3000 regulates pressurewithin the air mattress 4014. If the pressure of an air zone 4254, 4358,4360, 4390, and 4392 is too high, controller 3004 actuates theappropriate valve assembly actuator 564 to allow air to escape from theair zone 4254, 4358, 4360, 4390, and 4392. If the pressure is too low,microcontroller 3004 sends a message over network 510 to power supplymodule 514 of patient support 4010 (parts of which are generallydepicted in FIG. 124 as power supply 3006), and power supply 3006activates pump 4064. When microcontroller 3004 detects that pump 4064 isturned on, it actuates the appropriate valve assembly actuator 564 toallow air to enter the respective air zone 4254, 4358, 4360, 4390, 4392.

Among other things, embodiments of pressure control system 3000 includeone or more of the following functionalities: a process 3030 forcontrolling the inflation of air zones 4254, 4358, 4360, 4390, and 4392according to the size or weight of a patient, a process 3032 forcontrolling inflation of turn assist bladders 4358, 4360, a process 3070for controlling inflation of seat section 4392 of mattress 4014 inresponse to elevation of the head section 4038 of the deck 26′ and/or aprocess for controlling inflation of seat section 4392 of mattress 4014in response to the patient sitting up on the bed 4014 with little or nosupport by the head section 4038 of the deck 26′.

Mattress Pressure Dependency on Patient Weight

In certain illustrative embodiments of pressure control system 3000 ofdynamic surface module 518, a process 4730 for controlling the inflationof air zones 4254, 4358, 4360, 4390, and 4392 according to the size orweight of a patient disposed on patient support 4010 is provided. Oneillustrative embodiment of process 4730 is shown in FIG. 155 anddescribed below.

In certain illustrative embodiments as detailed above, an operator orcaregiver is required to select an appropriate patient weight. In stillother embodiments, the controller 3004 automatically selects a defaultsetting, e.g., the “medium” size, if a patient weight is not selected bythe operator or caregiver.

In yet another illustrative embodiment, pressure control system 3000automatically determines the patient's weight through measurements byweigh frame 36 and/or by a force sensor supported by seat section 40′.More particularly, and with reference to FIGS. 129 and 156, thepatient's weight is derived from an algorithm whose inputs include forcesensing resistors (FSRs) 5002, 5004, 5006, 5008, and 5010 supported onthe deck 26′ below the mattress 4014, and the four load cells 220, 222,224, and 226 forming a portion of the in-bed scale weighing system. Theload cells 220, 222, 224, 226 are coupled to the scale controller 5012,which is configured to perform diagnostic evaluations of the load cellsto determine if they are working properly. In the illustrativeembodiment, there are a total of five FSRs, including three FSRs 5002,5004, and 5006 supported by the head section 38′ of the bed deck 26′,and two FSRs 5008 and 5010 supported by the seat section 40′ of the beddeck 26′. The two FSRs 5008 and 5010 in the seat section 40′ and one ofthe FSRs 5004 in the head section 38′ are connected to a scalecontroller 5012. These FSRs 5004, 5008, and 5010 are used for a patientposition monitoring (PPM) system operated by the scale controller 5012and which is configured to notify a caregiver when the patient changesposition relative to the patient support 10′. The two additional FSRs5002 and 5006 in the head section 38′ are connected to the aircontroller 3004. These two additional FSRs 5002 and 5006 provideadditional detection coverage in the head section 4038, and also providea diagnostic function in order to allow the air controller 3004 todetermine when these FSRs 5002 and 5006 are disconnected ormalfunctioning.

The FSRs are of conventional design and have resistance values whichchange depending upon the amount of force applied thereto. FSRsgenerally comprise polymer thick film (PTF) devices which exhibit adecrease in resistance with an increase in the force applied to anactive surface. More particularly, the resistance of the FSRs drop belowa predetermined value when a certain force is applied. While forcesensing resistors (FSRs) are utilized in the illustrated embodiment, itshould be appreciated that other sensors for detecting the presence of apatient supported on the head section 4390 and the seat section 4392 ofthe mattress 4014 may be substituted therefore. Illustratively, the FSRsare available from Interlink Electronics of Camarillo, Calif. as partnumber 408.

Patient Weight Determination

As noted above, four load cells 220, 222, 224, and 226 are attached tothe four corners of the weigh frame 36 of the bed 10′. The summation ofthese four load cells 220, 222, 224, and 226, when their output isconverted to a weight, provide the total weight supported by the weighframe 36. The weight of weigh frame 36 and anything supported by weighframe 36, such as deck 26′, mattress 4014, any other bed componentssupported on weigh frame 36, and a patient, is transmitted to load cells220, 222, 224, 226. This weight deflects or otherwise changes acharacteristic of load cells 220, 222, 224, 226 that is detected todetermine the total weight supported thereby. By subtracting a knownweight of weigh frame 36, deck 26′, mattress 4014 and any other bedcomponents supported on weigh frame 36, the weight of the patientpositioned on patient support 10 can be determined. Additionaldescription of load cells and methods for determining a patient'sweight, position in the bed, and other indications provided by loadcells is provided in U.S. patent application Ser. No. 09/669,707, filedSep. 26, 2000, titled Load Cell Apparatus, to Mobley et al., and PCTinternational patent application Ser. No. PCT/US/08189, titled HospitalBed Control Apparatus, to Dixon et al., the disclosures of which areexpressly incorporated by reference herein. In one illustrativeembodiment, the load cells are available from HBM, Inc. of Marlborough,Mass. According to alternative embodiments of the present disclosure,other configurations and methods of using load cells or other devices todetermine a patient's weight or other information related to the patientknown to those of ordinary skill in the art are provided.

Information from the scale controller 5012 is transmitted to the aircontroller 3004 through the controller area network (CAN) 510. Theinformation is parsed into seven data sets (four load cells 220, 222,224, 226, three FSRs 5004, 5008, 5010) with each transmission beingspaced apart by approximately 100 milliseconds. Along with each data setis an error byte that contains diagnostic information pertaining to theload cells 220, 222, 224, 226.

Referring further to the flow chart of FIG. 155, the illustrativeprocess begins upon appropriate activation of the controller 3004 andwith the initialization of all variables. Next, the process continues atblock 4734, where the scale controller 5012 determines the weight of thepatient, as represented by the variable Patient_Weight. In theillustrative process 4730, the value of Patient_Weight is determined bythe subprocess 5020 illustrated in FIGS. 157 and 158.

Process 5020 begins at block 5022 with the initialization of allvariables. As detailed below, the variable Load_Beam_Offset is set toequal a value from the most recent operation of the controller 3004. Atdecision block 5024, the controller 3004 queries whether it is ready forprocessing data. More particularly, the controller 3004 determineswhether a complete set of data from the FSRs 5002, 5004, 5006, 5008,5010 and load cells 220, 222, 224, 226 is available for utilization. Asnoted above, a complete set of updated data is received every 700milliseconds. More particularly, seven packages of data are receivedfrom the scale controller 5012 at the rate of one package every 100milliseconds. Two additional packages of information are received fromthe first and third head section FSRs 5002 and 5006, one every 350milliseconds. If a complete new set of data from the FSRs 5002, 5004,5006, 5008, 5010 and the load cells 220, 222, 224, 226 is not available,then the process returns at block 5026 to start block 5022. If decisionblock 5024 is answered in the affirmative, then the process continues todecision block 5028 where the controller 3004 processes data from theFSRs 5002 and 5006 and the scale controller 5012. More particularly, theprocessor 3004 determines the value of the variable Load_Beam_Total tobe equal to the sum of the four inputs from the load cells 220, 222,224, 226. The controller 3004 further analyzes the values from the FSRs5002, 5004, 5006, 5008, 5010. If any of the FSRs 5002, 5004, 5006, 5008,5010 have a resistance indicating the presence of a patient, then thecontroller 3004 sets the flag Patient_Present to TRUE.

The process 5020 next continues to block 5030 where the controller 3004queries whether the data from both the FSRs 5002, 5004, 5006, 5008, 5010and the scale controller 5012 are stable. More particularly, thecontroller 3004 queries whether the patient has been consistentlydetected as being present or not present for a minimum predeterminedamount of time. In the illustrative embodiment, if (1) the patient hasbeen detected for at least approximately 3.5 seconds as indicated by theflag Patient_Present being set to TRUE, or (2) the patient has not beendetected for at least approximately 3.5 seconds as indicated by the flagPatient_Present being set to FALSE, then the FSR data is consideredstable. Similarly, if the Load_Beam_Total variable has not changed bymore than five pounds for at least approximately 3.5 seconds, then thescale data is considered stable. If the controller 3004 determines thatthe data is not stable at block 5030, then the process proceeds to block5026. If the data is considered stable, then the process 5020 thencontinues to process block 5032.

In one illustrative embodiment, the FSRs 5002, 5004, 5006, 5008, 5010are grouped into two sets, with the first group comprising all of theFSRs 5002, 5004, 5006, 5008, 5010, and the second group comprising thehead section FSRs 5002, 5004, 5006. In order for the FSR data to beconsidered stable by the controller 3004, then (1) all of the FSRs ineither the first group or the second group must not detect a patient forat least approximately 3.5 seconds, or (2) any of the FSRs in either thefirst group or the second group must detect a patient for at leastapproximately 3.5 seconds.

At block 5032, the controller 3004 recalculates the variableLoad_Beam_Adj. More particularly, the controller sets Load_Beam_Adj tobe equal to the variable Load_Beam_Total minus the variableLoad_Beam_Offset. As mentioned above, the variable Load_Beam_Offset issaved from the prior operation of the controller 3004. TheLoad_Beam_Offset is defined as the weight measured by the scalecontroller 5012 prior to a patient getting on the bed 10′ and beingsupported by the weigh frame 36, and following the addition of themattress 4014, footboard 18 and any other equipment supported by theweigh frame 36. The Load_Beam_Offset takes into consideration thefactory calibration, typically the zeroing or initializing of the weightmeasured by the scale controller 5012 without the mattress 4014,footboard 18, or other equipment supported by the weigh frame 36. Insummary, the Load_Beam_Offset is equal to a load applied to the weighframe 36 in excess of that when the bed 10′ is calibrated duringmanufacture and without the patient supported by the weigh frame 36.

The process 5020 then continues to decision block 5034, where thecontroller 3004 queries whether the conditions have been satisfied to“zero” the bed 10′. In other words, the controller 3004 determineswhether conditions are satisfied for recalculating the offset(Load_Beam_Offset) for the bed 10′. More particularly, the controller3004 queries whether (1) the variable Load_Beam_Adj is less than zero or(2) the variable Load_Beam_Adj is less than a maximum detected offsetvalue and the flag Patient_Present is FALSE. The first instance, wherethe Load_Beam_Adj is negative, could occur where equipment has beenremoved from the weigh frame 36 since the last operation of thecontroller 3004. As such, the value of the variable Load_Beam_Totalcould be less than the value of the variable Load_Beam_Offset as savedfrom the prior operation. The second instance, where the variableLoad_Beam_Adj is less than a maximum detected offset value and thePatient_Present flag is FALSE could occur where equipment has been addedto the bed 4010 and is supported by the weigh frame 36 since the lastoperation of the controller 3004, and no patient is detected as beingsupported by the deck 26′. If at block 5034, the controller 3004determines that the conditions are right to zero the bed 10′ then theprocess 5020 continues to block 5036. Illustratively, the maximumdetected offset value is defined as approximately 50 pounds.

At process block 5036, the controller 3004 calculates a new offset andclears the flag New_Offset_Pending. More particularly, the controller3004 equates the variable Load_Beam_Offset to the variableLoad_Beam_Total, and sets the New_Offset_Pending flag to FALSE. As such,the controller 3004 resets the Load_Beam_Offset to be equal to the valueof the Load_Beam_Total. The process then continues at block 5038 wherethe controller 3004 recalculates the variable Load_Beam_Adj. Moreparticularly, the controller 3004 equates the variable Load_Beam_Adj tobe equal to the variable Load_Beam_Total minus the variableLoad_Beam_Offset.

The process 5020 then continues to block 5040 where the controller 3004applies output filter and weight limits. More particularly, thecontroller 3004 updates the variable Patient_Weight only if (1) thevariable Load_Beam_Adj is greater than the variable Patient_Weight plusa minimum patient weight change or (2) the variable Load_Beam_Adj isless than the variable Patient_Weight minus the minimum patient weightchange. Illustratively, the minimum patient weight change is defined asapproximately ten pounds. If the variable Load_Beam_Adj is greater thana maximum patient weight, then the controller 3004 sets Patient_Weightto be equal to a default maximum patient weight. Illustratively, themaximum patient weight is defined as approximately 350 pounds, while thedefault maximum patient weight is defined as approximately 400 pounds.If the variable Load_Beam_Adj is less than a minimum patient weight,then the variable Patient_Weight is set to be equal to a default minimumpatient weight. Illustratively, the minimum patient weight and thedefault minimum patient weight are both set to be equal to approximately65 pounds. The process 5020 then continues to return block 5026 andsubsequently to decision block 5024.

Referring again to decision block 5034 of FIG. 157, if the conditionsare not proper for resetting the bed 4010 as detailed above, then theprocess 5020 continues to decision block 5042. At decision block 5042,the controller 3004 queries whether there is a possible large offset torecord. More particularly, the controller 3004 determines whether (1)the variable Load_Beam_Adj is greater than or equal to the maximumdetected offset value and (2) the flag Patient_Present is FALSE. Inother words, the controller 3004 determines whether a large load hasbeen measured by the weigh frame 36 and no patient is detected on thedeck 26′. As noted above, the maximum detected offset value isillustratively defined as approximately 50 pounds. If decision block5042 is answered in the affirmative, then the process 5020 continues toprocess block 5044.

At block 5044, the controller 3004 stores the pending offset and setsthe New_Offset_Pending flag. More particularly, the variablePending_Offset is set equal to the Load_Beam_Total and the flagNew_Offset_Pending is set to TRUE. The process 5020 then continues toprocess block 5040 and continues to operate as detailed herein as if apatient is present on the deck 26′.

Referring again to decision block 5042, if there is no possible largeoffset to record, then the process continues to decision block 5046(FIG. 158). At decision block 5046, the controller 3004 queries whetherthere is an existing pending offset. More particularly, the controller3004 queries whether the flag New_Offset_Pending is set to TRUE. Ifdecision block 5046 is answered in the negative, then the process 5020continues to process block 5040 (FIG. 34). If decision block 5046 isanswered in the affirmative, then the process 5020 continues to decisionblock 5048.

At decision block 5048 of FIG. 158, the controller 3004 queries whetherthe variable Load_Beam_Adj is much greater than the pending offset. Moreparticularly, the controller 3004 determines whether the variableLoad_Beam_Adj is greater than the variable Pending_Offset plus a minimumnew patient weight. Illustratively, the value of the minimum new patientweight is defined as approximately 90 pounds. If decision block 5048 isanswered in the negative, then the process 5020 continues to processblock 5050 where the New_Offset_Pending flag is cleared or set to FALSE.The process 5020 then continues to process block 5040 (FIG. 157). If thedecision block 5048 is answered in the affirmative, then the processcontinues to block 5052.

At block 5052, the controller 3004 updates the offset with the pendingoffset. More particularly, the controller 3004 sets a variableLoad_Beam_Offset to be equal to the variable Pending_Offset. Thesituation could occur where a patient is now present on the deck 26′ andthe prior pending offset value was equipment supported by the weighframe 36. The process then continues to process block 5054. At processblock 5054, the controller 3004 recalculates the variable Load_Beam_Adj.Again, Load_Beam_Adj is equal to the variable Load_Beam_Total minus thevariable Load_Beam_Offset. The process 5020 then continues to block 5050where the New_Offset_Pending flag is cleared or set to FALSE. Theprocess 5020 then continues to process block 5040 (FIG. 157) where thecontroller 3004 applies output filter and weight limits and updates thepatient weight if appropriate. The process 5020 then continues to thereturn block 5026 and subsequently to decision block 5024.

Once the value of the variable Patient_Weight has been determined, forexample by the above detailed process 5020, the process 4730 of FIG. 155continues at block 4736. At step 4736, the air zone(s) 4254, 4358, 4360,4390, and 4392 being monitored is determined. The bladders in the heelpressure relief member 4254, the head section 4390, the seat section4392, and the turn assist bladders 4358, 4360 may be inflated to varyingpressures based on patient weight, as represented by the variablePatient_Weight. However, it is understood that in alternativeembodiments not all of the air zones 4254, 4358, 4360, 4390, and 4392may be inflated based on patient weight.

At step 4736, process 4730 determines the desired inflation pressure forthe air zone(s) 4254, 4358, 4360, 4390, and 4392 being monitored basedon the patient weight. In the illustrated embodiment, microcontroller3004 obtains the desired pressure for the air zone(s) 4254, 4358, 4360,4390, and 4392 from data, such as one or more look-up tables, stored inmemory 3010. The desired pressure may be a discrete value, a range ofpermissible values, or calculated from an equation or algorithm as afunction of patient weight. Also, the desired pressure may be differentfor each air zone 4254, 4358, 4360, 4390, and 4392. Further, variousother factors, including environmental factors such as temperatureand/or altitude, may affect the desired pressure values and be reflectedin data in the look-up table.

As detailed in Table 7, in the illustrated embodiment the appropriatepressures for the seat section 4392, in pressure relief and turn assistmodes of operation, also depends on the elevation of head section 38′,as represented by the variable Head_Elevation. Thus, for seat section4392, the appropriate pressure is determined by reference to bothpatient weight and head angle. However, adjusting the pressure of seatsection 4392 based on only one of these criteria, regardless of the modeof operation, is also within the scope of the present invention.

Mattress Seat Section Boost

As may be appreciated, when the head section 38′ is elevated, a portionof the patient's weight naturally shifts from being supported by thehead section 4390 of the mattress 4014 to the seat section 4392 of themattress 4014. To compensate for this weight shift, the inflationpressure of the seat section 4392 is adjusted in response to changes inthe position of the head section 4038. In the illustrated embodiment,and as shown in Table 7, the pressure in the seat section 4392 isdependent upon the elevation of the head section 4390 only during thepressure relief and turn assist modes of operation. In other words, thepressure in the seat section 4392 is not varied in response to changesin elevation of the head section 4390 in the max inflate, CPR, orpost-turn assist modes of operation.

Illustratively, the position of head section 38′, or head angle, isdetermined by position detector 606. In the illustrated embodiment, apotentiometer reading corresponding to the head angle is determined bylogic module 512 and reported to dynamic surface module 518 via network510 for use in process 4730. Additional details regarding operation ofthe potentiometer for determining head angle is detailed above.

In determining the pressure for the seat section 4392 at block 4738, themicrocontroller 3004 compares the angle as determined by the positiondetector 606 to data stored in memory 3010, such as those valuescontained in Table 10 below. The ranges of values for adjacent angularregions indicating a change in head elevation in Table 10 overlap, inorder to take into consideration hysteresis (dependence of the state ofa system on its previous history, generally in the form of a lagging ofa physical effect behind its cause) in the head angle evaluation.

TABLE 10 HEAD ELEVATION ANGLE Head Elevation Angle Regions Angle Used inAngular Minimum Maximum Calculations for Region Angle Angle ToleranceHead_Elevation 0  0° 30° +/−3° 30° 1 26° 40° +/−3° 40° 2 36° 50° +/−3°50° 3 46° 60° +/−3° 60° 4 56° 65° +/−3° 65°

For example, head section 38′ will be considered to have moved fromregion 0 (zero) to region 1 (one) if the position detector 606 measuresa head angle of between approximately 30 and 40 degrees. However, oncehead section 38′ is in region 1 (one), it will not be considered to havemoved back to region 0 (zero) unless the position detector 606 measuresa head angle below region 1 (one), e.g., approximately 26 degrees orless, is received. Further, as indicated in Table 10, the variableHead_Elevation for use in pressure calculations is set to apredetermined value for each region of measured head elevation. Forexample, in region 1 (one), the variable Head_Elevation is set to 40degrees, while in region 2 (two), the variable Head_Elevation is set to50 degrees.

If a change in position occurs in the downward direction, from oneangular region to a different angular region, i.e., head section 4038 islowered from region 2 (two) to region 1 (one) in Table 10, then at step4738 the desired pressure of seat section 4392 is decreased according tothe weight of the patient, represented by Patient_Weight, and thecurrent head angle set as Head_Elevation. The desired pressure range(Pressure_Seat range) is determined by reference to a look-up tablestored in memory 3010. Table 7 is an example of such a table.

If a change in position occurs in the upward direction, from one angularregion to a different angular region, i.e., head section 38′ is elevatedfrom region 0 (zero) to region 1 (one) in Table 10, then at step 4738the desired pressure of seat section 4392 is increased according to theweight of the patient, represented by the variable Patient_Weight, andthe current head angle set as Head_Elevation. In addition, a “seatboost” may be applied to seat section, as detailed below, meaning thatseat section 4392 is initially over-inflated for a brief period of timeto compensate for the above-mentioned weight shift.

At step 4740, microcontroller 3004 measures the current pressure asdescribed above and determines whether the current pressure is lessthan, equal to, or greater than the desired pressure determined asdescribed above. At block 4742, the microcontroller 3004 queries whetherthe actual pressure is greater than the desired pressure determined atstep 4738 above. If so, then at step 4744, the zone is deflated to thedesired pressure. At block 4746, the microcontroller 3004 querieswhether the current pressure is less than the desired pressure. If so,the microcontroller 3004 commands power supply 3006 to activate pump4064 to inflate bladders 2304 to the desired pressure as describedabove, at step 4738.

After the pressure is decreased or increased at blocks 4744 and 4748,respectively, the process 4730 continues to block 4750. At block 4750,the controller 3004 determines if the seat section 4392 requires apressure “boost.”

In addition to other functions discussed above and elsewhere in thisdisclosure, pressure control system 3000 may perform additionalprocesses 4800, 4900 for increasing or “boosting” the inflation of seatsection according to the elevation of head section 4038. One embodimentof such method is shown in FIG. 160 and described below.

As noted above, when head section 38′ is elevated, a portion of thepatient's weight naturally shifts from head section 4390 of the mattress4014 to seat section 4392 of the mattress 4014. A similar weight shiftoccurs when the patient sits up in the bed 10′ such that the patient'sweight is supported mostly or entirely by the seat section 4392. Toanticipate this weight shift and prevent “bottoming out,” the inflationpressure of seat section 4392 is boosted in response to changes in theposition of head section 38′. Table 11 shows boost pressure ranges forseat section depending on ranges of patient weight.

TABLE 11 SEAT BOOST PRESSURE (in H₂O) Patient_Weight MODE >0, ≦140 >140,≦260 >260 Head Angle Increase* 10.0-20.0 15.0-21.0 19.0-29.0 Sitting-Up10.0-20.0 15.0-21.0 19.0-29.0 *Duration of Head Angle Increase Boost: 15seconds ± 5 seconds; Head Angle Change Required for Boost: +3° ± 1.5°

Process 4800 begins at block 4802 with the determination of theelevation of the head section (Head_Elevation), in the manner detailedabove. At decision step 4804, process 4800 evaluates the input receivedfrom logic module 512 and determines whether head section 38′ hasexperienced at least a 3 degree increase in position by comparing thecurrent head angle to the previous head angle. If the head angle hasincreased by at least approximately 3 degrees, the process 4800continues to step 4806. If the head section 38′ has not been elevated byat least approximately 3 degrees, then process 4800 returns to step4802. It is understood that 3 degrees is an exemplary value and that achange in the head angle may be indicated by a greater or lesser valueas appropriate. Of course, during this time, pressure control system3000 continues to periodically measure the pressure of the seat section4392 to make sure that it is within the desired ranges.

It should be appreciated that if a change in position occurs in thedownward direction, i.e., head section 38′ is lowered, then at step 4804no pressure increase in the seat section 4392 is triggered. If a changein position occurs in the upward direction by at least 3 degrees, i.e.,head section 38′ is elevated, then at step 4806 the inflation pressureof seat section is increased. In other words, a “seat boost” is appliedto seat section 4392, meaning that seat section 4392 is initiallyover-inflated for a brief period of time to compensate for theabove-mentioned weight shift. At block 4808, a timing decision isexecuted by the controller 3004 to determine if the pressure boostexceeds a predetermined time, illustratively between 1 second and 30seconds. In one illustrative embodiment, the predetermined time is setat approximately 15 seconds. If the pressure boost does not exceed thepredetermined time, then the pressure boost continues at block 4806. Ifthe predetermined time has passed, then the process 4800 continues toblock 4810, where the pressure boost is terminated.

Examples of the initial “seat boost” pressures are shown in Table 11.After the seat boost period expires, process 4800 adjusts the pressureof seat section 4392 to the desired level based on patient weight andhead angle, as determined by the look-up Table 7 as detailed above.

Referring now to FIG. 161, process 4900 for providing a sudden elevationor “boost” of pressure in the seat section 4392 likewise is triggeredwhen the patient Sits up in the bed 10′ such that the patient's weightis supported mostly or entirely by the seat section 4392. Process 4900begins at block 4902 with the controller 3004 monitoring the patientsensors or FSRs 5002, 5004, 5006, 5008, 5010. At decision block 4904,the controller 3004 queries whether the head section patient sensors orFSRs 5002, 5004, 5006 detect the presence of a patient in the headsection 38′. If block 4904 is answered in the affirmative, then theprocess returns to block 4902 and the controller 3004 continuesmonitoring the FSRs 5002, 5004, 5006, 5008, 5010. If at block 4904 thehead section FSRs 5002, 5004, 5006 do not detect a patient, then theprocess continues to block 4906.

At decision block 4906, the controller 3004 queries whether the patientweight (Patient_Weight) is greater than a predetermined amount. In theillustrative embodiment, the predetermined amount is approximately 100pounds. If the value of Patient_Weight is not greater than approximately100 pounds, then the process returns to block 4902. In other words, theno pressure boost will occur in the seat section 4392 if the determinedpatient weight is not greater than approximately 100 pounds. If thevalue of Patient_Weight is greater than approximately 100 pounds, thenthe process 4900 continues to block 4908 where the inflation pressure ofseat section 4392 is increased. In other words, a “seat boost” isapplied to seat section 4392, meaning that seat section 4392 isinitially over-inflated for a brief period of time to compensate for theabove-mentioned weight shift. The seat boost continues indefinitely aslong as the decision blocks 4904 and 4906 are answered affirmatively. Ofcourse, during this time, pressure control system 3000 continues toperiodically measure the pressure of the seat section 4392 to make surethat it is within the desired ranges.

Examples of the initial “seat boost” pressures are shown in Table 11.After the seat boost period expires, process 4900 adjusts the pressureof seat section 4392 to the desired level based on patient weight andhead angle, as determined by the look-up Table 7 as detailed above.

Patient Turn Assist

In addition to other functions discussed above and elsewhere in thisdisclosure, pressure control system 3000 of dynamic surface module 518controls the operation of turn assist bladder assembly 4220 during theturn assist mode of operation. Turn assist bladders 4358, 4360 areconfigured to be selectively inflated to assist a caregiver in turningor rotating a patient, e.g., for therapy or treatment reasons. Oneembodiment of a process 3032 for controlling operation of turn assistbladders 4358, 4360 is shown in FIG. 159 described below. Process 3032is implemented using application software stored in memory 3010 ofmicrocontroller 3004. The structure of turn assist bladders 4358, 4360is described elsewhere in this application.

At step 3034 of FIG. 159, process 3032 detects whether a request hasbeen received to activate one of turn assist bladders 2262, 2264. In theillustrated embodiment, such a request is initiated by an operator orcaregiver activating one of the turn assist buttons 1624, 1626 (FIG. 75)located on siderail controllers 52, 54. However, it is understood thatother means for activating the turn assist may be used. For example,control system 44 may be programmed to automatically activate one ormore of the turn assist buttons 1624, 1626 at scheduled times during theday or night.

At decision step 3036, prior to initiating the turn assist function,process 3032 checks to make sure that the siderails 4020, 4022 locatedon the side of patient support 10′ that the patient is being turnedtoward are in the up position, based on signals provided by siderailposition detectors 60. If one or more of siderails 4020, 4022 on theside of patient support 10′ toward which the patient is being turned isnot in the up position, an error signal is generated at step 3038 andprocess 3032 ends. In the illustrated embodiment, an audible or visualsignal is generated for a brief period or until the siderail orsiderails 4020, 4022 are brought to the up position. Thus, in theillustrated embodiment, the siderails 4020, 4022 toward which thepatient is being turned must be in the up position in order for the turnassist process to initiate. It is possible, however, that in otherembodiments, a caregiver or operator may override this restriction, orthat this restriction may be made optional, for example, depending onthe circumstances of a particular patient.

At step 3040, process 3032 checks to see if the angle of head section38′ (Head_Elevation) is less than, equal to, or greater than apredetermined maximum angle. In the illustrated embodiment, the maximumhead angle is about 25°. In one embodiment, signals are provided by theposition detector 606 directly to the dynamic surface module 518, whichdetermines the head angle. Alternatively, the head angle determinationis made by logic module 512 which reports the head angle to dynamicsurface module 518 for use in process 3032, via CAN network 510. If thehead angle is less than or equal to 25°, then the turn assist processcontinues to step 3044. However, if the head angle is greater than about25°, an error signal is generated at step 3042, and the turn assistprocess is not permitted to continue.

At step 3044, the weight of the patient (Patient_Weight) being supportedby patient support 10′ is determined as described above so that adesired pressure based on patient weight is applied to the selected turnassist bladder 4358, 4360.

At step 3046, if first turn assist button 1624 is activated, first turnassist bladder 4358 inflates to rotate a person in patient support 10′upwardly in a counter-clockwise from the perspective of a personstanding behind head section 38′. If second turn assist button 1626 isactivated, second turn assist bladder 4360 inflates to rotate the personupwardly in the opposite direction as rotated in response to activationof first turn assist button 1624. Inflation of the selected turn assistbladder 4358, 4360 raises one side of the patient to a predeterminedangle. In the illustrated embodiment, the selected turn assist bladder4358, 4360 inflates to rotate the patient onto his or her side at abouta 20 degree angle with respect to mattress 4014, in approximately 20-50seconds, depending on the weight or size of the patient. It isunderstood that the predetermined angle and speed of inflation may bechanged or modified as needed based on a variety of factors, includingthe purpose for rotating the patient.

A timer is set at step 3048 when the selected turn assist bladder 4358,4360 is inflated. The selected turn assist bladder 4358, 4360 remainsinflated for a predetermined period of time and is then automatically“reset” or deflated. The predetermined time is empirically determined bythe needs and desires of the patient and caregiver in an operatingenvironment and illustratively is a time within a range of approximately5 seconds to approximately 5 minutes. In the illustrative embodiment,the duration of turn assist inflation is about 10 seconds. At step 3050the timer counts out this wait period. After the wait period is complete(e.g., after 10 seconds), an audible or visual signal is generated toindicate to the patient and caregiver that the selected turn assistbladder 4358, 4360 is about to enter a “post-turn assist” mode or phase.

In the post-turn assist mode, process 3032 begins deflating the selectedturn assist bladder 4358, 4360 at step 3052. In the illustratedembodiment, deflation is expedited by quickly “hyperinflating” bladdersof the head and seat sections 4390 and 4392 to a firm, “post-turnassist” inflation pressure (see, e.g., Table 6 and Table 7). Inflationof head and seat sections 4390 and 4392 exerts pressure on turn assistbladders 4358, 4360 causing turn assist bladders 4358, 4360 to expel airmore rapidly. Alternatively, a vacuum mechanism may be coupled to turnassist bladders 4358, 4360 to accelerate deflation.

Monitor activity step 3060 is a step that is periodically executedduring the turn assist operation. This process detects whether a patientor caregiver attempts to utilize other bed features while the turnassist is in operation. Additional details regarding the operation ofthe dynamic surface module are provided above.

CPR Configuration

Patient support 10′ may be placed in the preferred CPR configuration byproviding an indication to control system 44 which in turn controlsactuators 48 c, 48 d, 48 e to place head, seat, and leg sections in agenerally linear relationship, controls pump 4064, to inflate upperbladder assembly 4222 to the desired pressures, and controls decksupport 24 to lower a head end relative to a foot end. In theillustrative embodiment, the control system 44 inflates the bladderassembly 4394 of the head section 4390 to its desired CPR pressurebefore it inflates the bladder assembly 4396 of the seat section 4392 toits desired CPR pressure. As such, the head section 4390 reaches itsdesired firmness prior to the seat section 4392. This functionality isdesirable since CPR procedures typically require pressure to be appliedto the upper torso or chest of a patient.

Mattress Air Pump

Pump 64 is configured to provide pressurized air to manifold 62 and thepneumatic devices of mattresses 14, 4014. As shown in the illustrativeembodiment of FIGS. 162 and 163, pump 64 includes a support bracket 5440coupled to a strut 211 of weigh frame 36, a pump cover support plate orbracket 5444 supported by support bracket 5440, a pump cover 5446supported by housing support bracket 5444, a pump unit support bracket5448 also supported by housing support bracket 5444, a pump unit 5450supported by pump unit support bracket 5448, and a filter and mufflerunit 5452 supported on the outside of pump cover 5446.

Many pump units, such as pump unit 5450, create noise and vibrationduring operation. Several of the components of pump 64 are configured toreduce the transmission of the noise and vibration generated by pumpunit 5450.

As shown in FIGS. 113 and 162-164, support bracket 5440 includes a pairof saddle-shaped portions 5454 that hook or loop over strut 211 and fourarms 5456 that extend down from saddle-shaped portions 5454. U-shapedrubber or elastic members 5458 (only one is shown in FIG. 163) arepositioned between saddle-shaped portions 5454 and strut 211 as shown inFIG. 164 to reduce the vibration transmitted from pump 64 to strut 211.

Saddle-shape portions 5454 includes apertures 5460 sized to receivefasteners 5462 that couple bracket 5440 to strut 211. Similarly, strut211 includes apertures 5464 sized to receive fasteners 5462. Howeverapertures 5464 are large enough that strut 211 does not come intocontact with fasteners 5462 to avoid a direct, rigid coupling betweenbracket 5440 and strut 211 (FIG. 164). Rather coupling occurs throughU-shaped rubber members 5458.

Pump cover support bracket 5444 includes four arms 5466 that includefastener-receiving notches 5468. Rubber or elastic grommets 5470 (onlyone is shown in FIG. 163) are provided that are received in each ofnotches 5468. Each grommet 5470 includes two head portions 5472, anannular groove 5474 defined between head portions 5472, and afastener-receiving aperture (not shown) sized to receive fasteners 5476therethrough.

Grommets 5470 are positioned in notches 5468 so that head portions 5472overlaps portions of arms 5466 and portions of arms 5466 are positionedin grooves 5474. As shown in FIG. 162, lower head portions 5472 ofgrommets 5470 are positioned on top of arms 5456 of support bracket 5440so that lower head portions 5472 are positioned between support bracket5440 and pump cover support bracket 5444. Fasteners 5476 extends throughgrommets 5470 so that upper head portions 5472 are positioned betweenhead portions of fasteners 5476 and arms 5466 and a nut (not shown)coupled to lower thread portions of fasteners 5476 abut the undersidesof arms 5456. Because portions of grommets 5470 are positioned betweenfasteners 5476 and arms 5466, 5456, no rigid, direct coupling isprovided between pump cover support bracket 5444 and support bracket5440.

Pump cover 5446 is coupled to pump cover support bracket 5444 by aplurality of fasteners 5478. A foam gasket 5480 is compressed betweenpump cover bracket 5444 and pump cover 5446 to reduce the transmissionof noise and vibration. Similarly, a foam lining 5482 is provided on theinterior surfaces of pump cover 5446. According to an alternativeembodiment of the present disclosure a foam lining is also provided onthe underside of pump cover support bracket 5444.

Pump unit support bracket 5448 is welded or otherwise rigidly coupled tothe underside of pump cover support bracket 5444 so that pump unitsupport bracket 5448 is suspended within an interior region 5484 definedby foam lining 5482. Preferably, no portion of pump unit support bracket5448 or pump unit 5450 touch foam lining 5482.

Pump unit 5450 is supported on pump unit support bracket 5448 by atleast four resilient feet 5486 (only one such foot is shown in FIG. 163)made of a rubber material. As shown in FIG. 166, each foot 5486 includesfour annular head portions 5488 that define annular grooves 5490therebetween, a support portion 5492 positioned between head portions5488, and two pull portions 5494 positioned at opposite ends. As shownin FIGS. 163 and 166, pump unit 5450 illustratively includes a pluralityof apertures 5496 and pump unit support bracket 5448 includes aplurality of apertures 5498 sized to receive feet 5486. To install feet5486, an assembler inserts pull portions 5494 through respectiveapertures 5496, 5498 and pulls on pull portions 5494 until theupper-most and lower most head portions 5488 are pulled throughrespective apertures 5496, 5498. After assembly, portions of pump unitsupport bracket 5448 and pump unit 5450 are positioned in annulargrooves 5490 as shown in FIG. 166.

An alterative embodiment resilient foot 5510 is shown in FIG. 167coupled to pump unit 5450 and pump unit support bracket 5448. Resilientfoot 5510 includes a body portion 5512 made of a rubber or elasticmaterial, a nut 5514, and a threaded stud 5516. Body portion 5512 ismolded around nut 5514 and threaded stud 5516. To couple foot 5510 topump unit 5450 and pump unit support bracket 5448, a bolt 5518 isthreaded into nut 512 and a nut 5520 is threaded onto stud 5516.Preferably, portions of body portion 5512 are positioned between nut5514 and pump unit 5450 and between stud 5516 and pump unit supportbracket 5448 to provide increased frictional contact therebetween.

As shown in FIG. 162, a lower end of filter and muffler unit 5452 ispositioned in an inverted cover or pan 5522 of pump cover 5446. Pan 5522includes three side walls 5524, 5526, 5528 and a bottom wall 5530. Sidewalls 5524, 5526, 5528 cooperate to form a pair of slits or inlets 5532therebetween and side wall 5526 includes a pair of apertures 5534. Asshown in FIG. 165, lower end of filter and muffler unit 5452 is spacedapart from bottom wall 5530 by a distance 5531 so that a downwardlyfacing inlet 5536 of filter and muffler unit 5452 is spaced apart andfacing bottom wall 5530. A cable tie 5538 is provided that wraps aroundfilter and muffler unit 5452 and extends through apertures 5534 tocouple filter and muffler unit 5452 to side wall 5526.

If liquid is sprayed into or otherwise enters pan 5522, it will drainout of slits 5532. Furthermore, because inlet 5536 is facing andrelative close to bottom wall 5530, liquid cannot be sprayed into inlet5536 through slits 5532 from outside of pan 5522 because the pathbetween slits 5532 and inlet 5536 is non-linear. Thus, pan 5522 blocksany direct spray path into inlet 5536 so that it is difficult for liquidto inter filter and muffler unit 5452.

Preferably, filter and muffler unit 5452 is configured to filter outmany impurities in the air so that these impurities are not introducedto pump unit 5450, manifold 62, or mattress 14. With further referenceto FIGS. 163 and 165, air from filter and muffler unit 5452 iscommunicated to pump unit 5450 through tube 5540 coupled to an outlet5542 of filter and muffler unit 5452. Tube 5540 extends through atube-receiving notch 5544 in pump cover support bracket 5444 shown inFIG. 103 and couples to an inlet fitting 5546 of pump unit 5450.

During operation, pump unit 5450 generates noise that can travel throughtube 5540. Filter and muffler unit 5452 is configured to attenuate thisnoise so that it is not introduced into the patient environment.

Another tube 5548 is coupled to an outlet fitting 5550 of pump unit 5450that supplies pressurized air to manifold 62. Tube 5548 extends throughanother tube-receiving notch 5552 in pump cover support bracket 5444.Tube 5548 extends along strut 211 of weight frame 36 as shown in FIG. 18until it reaches longitudinally extending member 198 of weigh frame 36.As shown in phantom in FIG. 18, tube 5548 extends toward foot end ofpatient support 10 along an inner side of longitudinally extendingmember 198 until it reaches a middle portion thereof. Then, tube 5548turns inward toward the center of patient support 10. As shown in FIG.13, tube 5548 extends through an aperture 5556 and extends up headsection 38 of deck 26 between two strut members 5558 (shown best in FIG.45) of head section 38 until it reaches T-connector 2412 of manifold 62as shown in FIGS. 117 and 118.

A further illustrative embodiment mattress air pump 4064, as shown inFIGS. 168 and 170, includes a support bracket 5640 coupled to strut 211of weigh frame 36, a pump cover support plate or bracket 5644 supportedby support bracket 5640, a pump cover 5646 supported by housing supportbracket 5644, a pump unit support bracket 5648 also supported by housingsupport bracket 5644, a pump unit 5650 supported by pump unit supportbracket 5648, and a filter and muffler unit 5652 supported inside pumpcover 5646. Pump unit 5650 draws air through filter and muffler unit5652 from outside of pump 4064 and provides the air to manifold 62.

As shown in FIGS. 169 and 170, support bracket 5640 includes a saddlemember 5654 that hangs from strut 211 and a support member 5657 havingfour arms 5656 that extend away from saddle member 5654. A pair ofrubber or elastic grommets 5658 are positioned between respective tabsets 5659 of saddle member 5654 and strut 211 as shown in FIG. 170 toreduce the vibration transmitted from pump 4064 to strut 211. Steelsleeves 5661 (only one is shown in FIG. 169) are welded in place withinstrut 211 to receive grommets 5658.

Tab sets 5659 includes apertures 5660 sized to receive fasteners 5662that couple bracket 5654 to strut 211. Similarly, strut 211 includesapertures 5664 sized to receive steel sleeve 5661. When positioned inapertures 5664, portions of steel sleeves 5661 extend below the bottomof strut 211 as shown in FIG. 170. Steel sleeves 5661 are welded tostrut 211 along two lines 5665 (as shown in FIG. 169) defined betweenthe bottom of strut 211 and sleeve 5661.

Steel sleeves 5663 (only one is shown in FIG. 169) are positioned inrespective grommets 5658 to receive fasteners 5662. Grommets 5658 aresandwiched or positioned between strut 211 and bracket 5654 and strut211 and fasteners 5662 to avoid a direct, rigid coupling between bracket5654 and strut 211. Rather, the coupling occurs through grommets 5658.

Pump cover support bracket 5644 includes four arms 5666 that includefastener-receiving notches 5668. Resilient bushings 5670 and providedthat are received in each of notches 5668. Bushings 5670 are positionedin notches 5668 so that upper head portions 5671 of bushings 5670overlap portions of arms 5666 and a shank portions 5673 are positionedin notches 5668 as shown in FIG. 173. Resilient washers 5675 arepositioned on top of arms 5656 of support bracket 5640 so that the lowerhead portions are positioned between support bracket 5640 and pump coversupport bracket 5644. Fasteners 5676, such as machine screws, extendthrough metal washers 5677 and bushings 5670 so that washers 5677 andupper head portions 5671 of bushings 5670 are positioned between headportions of fasteners 5676 and arms 5666. Fasteners 5676 are screwedinto arms 5656. Because portions of bushings 5670 and washers 5675 arepositioned between fasteners 5676 and arms 5666, 5656, no rigid, directcoupling is provided between pump cover support bracket 5644 and supportbracket 5640.

Bushings 5670 and wasters 5675 are preferable made of thermoset,polyether-based, polyurethane material sold under the name SORBOTHANE bySorbothane, Inc. of Kent, Ohio. SORBOTHANE-brand material is avisco-elastic material. According to alternative embodiments, otherresilient or elastic materials such as rubber are used for the bushingsand washers.

Pump cover 5646 is coupled to pump cover support bracket 5644 by aplurality of fasteners 5678. As shown in FIG. 171, a foam lining 5680 isprovided in an interior region 5684 defined by pump cover 5646 and pumpcover support bracket 5644 to reduce the transmission of noise andvibration. Foam lining 5680 includes a foam top 5682 adhered to pumpcover support bracket 5644, a foam wall 5683 adhered to the walls ofpump cover 5646, and a foam bottom 5685 adhered to the bottom of pumpcover 5646. Foam top 5644 provides a seal between pump cover 5646 andpump cover support bracket 5644. Foam lining 5680 is made of acousticdamping material to attenuate noise introduced inside pump cover 5646.

Pump unit support bracket 5648 is welded or otherwise rigidly coupled tothe underside of pump cover support bracket 5644 so that pump unitsupport bracket 5648 is suspended within an interior region 5684 definedby foam lining 5680. As shown in phantom in FIG. 171, pump unit 5650extends into and compresses portions of foam lining 5680.

Pump unit 5650 is supported on pump unit support bracket 5648 by atleast four resilient feet 5686 (only two such feet are shown in FIG.169) made of a rubber or elastic material. Additional description ofsuitable resilient feet 5686 is provided above.

As shown in FIG. 171, filter and muffler unit 5652 is held in interiorregion 5684 by a flange 5688 welded to a sidewall 5690 of pump cover5646. Before assembly, flange 5688 toward the center of pump cover 5646.During assembly, filter and muffler unit 5652 is positioned adjacentflange 5688. Flange 5688 is then bent toward sidewall 5690 to theposition shown in FIG. 169 to press filter and muffler unit 5652 intofoam lining 5680 as shown in FIG. 171.

As shown in FIG. 171, an inlet 5710 of filter and muffler unit 5652 iscoupled to a tube or hose 5712 that extends through an aperture or inlet5714 in pump cover 5646. A grommet 5716 is positioned in aperture 5714to provide a seal between tube 5712 and pump cover 5646. A tube cover5718 is welded to pump cover 5646 that cover an end 5713 of tube 5712extending out of pump cover 5646. Tube cover 5718 includes threesidewalls 5720, 5722, 5724 and a top wall 5726. Sidewalls 5720, 5722,5724 cooperate with pump cover 5646 to form an aperture or inlet 5728.

If liquid is sprayed into or otherwise enters cover 5646, it will drainout of aperture 5728. Furthermore, because end 5713 of tube 5712 isfacing and relative close to wall 5722 of cover 5718, liquid cannot bedirectly sprayed into inlet end 5713 of tube 5712 through aperture 5728from outside of pan cover 5718 because the path between aperture 5714and aperture 5728 is non-linear. Thus, cover 5718 blocks any directspray path into end 5713 of tube 5712 so that it is difficult for liquidto enter filter and muffler unit 4652.

Interior components (not shown) of filter and muffler unit 5652 filterout many impurities in the air so that these impurities are notintroduced to pump unit 5650, manifold 62, or mattress 4014. Air fromfilter and muffler unit 5652 is communicated to pump unit 5650 throughinterior region 5684 from an outlet 5642 of filter and muffler unit5652. During operation of pump unit 5650, air from interior region 5684is drawn into an inlet 5730 of pump unit 5650 that is spaced apart fromfilter and muffler unit 5652. This creates negative pressure withininterior region 5684. Because of the pressure difference betweeninterior region 5684 and the environment outside of pump 5660, air isdrawn into interior region 5684 through filter and muffler unit 5652.This air enters interior region 5684 defined by foam lining 5680 beforeentering into inlet 5730 of pump unit 5650. Thus, foam lining 5680defines a portion of the path of travel of the air through pump unit5650.

Because inlet 5730 of pump unit 5650 is not directly coupled to filterand muffler unit 5652, noise exiting pump unit 5650 is not directlytransmitted to filter and muffler unit 5652. This noise exits pump unit5650 into interior region 5684 and is attenuated by foam lining 5680.Any noise that enters outlet 5642 of filter and muffler unit 5652 frominterior region 5684 is attenuated further by filter and muffler unit5652. Furthermore, because pump unit 5650 is not directly coupled tofilter and muffler unit 5652, most vibration generated by pump unit 5650is not transmitted outside of pump 4064 by tube 5712.

Another tube 5732 is coupled to an outlet fitting 5734 of pump unit 5650that supplies pressurized air to manifold 62. Tube 5732 extends throughan aperture 5736 in pump cover support bracket 5644. A grommet 5738 ispositioned in aperture 5736 to provide a seal between tube 5732 and pumpcover support bracket 5644. As shown in FIG. 172, support member 5657includes a notch 5739 that provides clearance for tube 5732 to extendthrough support member 5657. Pump unit 5650 also includes a power cord5740 that extends through a cord-receiving notch 5742 in pump coversupport bracket 5644 and couples to the power supply.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe spirit and scope of the invention as described and defined in thefollowing claims.

1. A patient support comprising, a frame positioned to support amattress, the frame including a base frame supported by a floor, anintermediate frame positioned over the base frame, a first pair of liftarms coupled together at a first end by a first cross member, and, asecond pair of lift arms coupled together at a first end by a secondcross member, the first ends of the first pair of lift arms beingconfigured to slide along at least one of the base frame and theintermediate frame, the first ends of the second pair of lift arms beingconfigured to slide along at least one of the base frame and theintermediate frame, and at least one actuator configured to move theintermediate framerelative to the base frame between first and secondpositions, during movement of the intermediate frame between the firstand second positions, a distance between the first and second crossmembers increases to provide clearance for at least one of theintermediate frame and the base frame; wherein the intermediate frame ispositionable between the first and second cross members when theintermediate frame is in the second position.
 2. The patient support ofclaim 1, wherein the lift arms slide along the base frame.
 3. Thepatient support of claim 1, wherein the intermediate frame is positionedabove the first and second cross members when the intermediate frame ispositioned in the first position and the intermediate frame ispositioned between the first and second cross members when theintermediate frame is in the second position.
 4. The patient support ofclaim 1, wherein the first pair of lift arms further includes a pair oflinks extending between the base frame and intermediate frame and a pairof guide links coupled to midpoints of the links and at least one of thebase frame and intermediate frame.
 5. The patient support of claim 1,wherein the base frame and intermediate frame nests together.
 6. Thepatient support of claim 1, wherein the lift arms are positioned betweenthe intermediate frame and the base frame when the intermediate frame isin the second position.
 7. The patient support of claim 1, wherein thefirst and second cross members extend transversely relative to alongitudinal axis of the frame.
 8. The patient support of claim 1,further comprising means for providing pressurized air to a mattresssupported by the frame, means for blocking egress of a patient from themattress, foot control means for operating features of the patientsupport, power and control means for providing power and control to theactuator, rotational support means configured to permit movement of theframe on a floor, control means for controlling features of the patientsupport, the control means being removably coupled to the blockingmeans, mattress control means for controlling operation of the mattress,power supply means for providing power to components of the patientsupport, and network means for communicating between at least two of thepower and control means, the control means, the block means, andmattress control means.
 9. A patient support comprising, a base frame,an intermediate frame, and a lift mechanism configured to move theintermediate frame between raised and lowered positions relative to thebase frame, at least one of the base and intermediate frames defining aninterior region in which the other of the at least one of the base andintermediate frames is positioned when the intermediate frame is in thelowered position, at least one of the base and intermediate framesincluding transverse step members extending from the interior region andcoupling the intermediate frame to a weigh frame.
 10. The patientsupport of claim 9, wherein the weigh frame is supported by theintermediate frame and a plurality of load cells are supported by thetransverse step members.
 11. The patient support of claim 9, wherein theintermediate frame includes the transverse step members.
 12. The patientsupport of claim 11, wherein the transverse step members are positioneddirectly over the base frame.
 13. The patient support of claim 12,wherein the base frame includes a pair of longitudinally extendingmembers and the transverse step members are positioned directly over thelongitudinally extending members of the base frame.
 14. The patientsupport of claim 9, further comprising a pair of lift arms configured tomove the intermediate frame relative to the base frame between raisedand lowered positions, the lift arms being positioned in a space definedbetween longitudinally extending members of the base and intermediateframes when the intermediate frame is in the lowered position.
 15. Thepatient support of claim 9, wherein at least two of the transverse stepmembers extend in opposite directions and at least two of the transversestep members extend in the same direction.
 16. A patient supportcomprising, a base frame, an intermediate frame, and a lift mechanismhaving an end connected to the base frame and another end connected tothe intermediate frame and configured to move the intermediate framebetween raised and lowered positions relative to the base frame, atleast one of the base and intermediate frames defining an interiorregion in which the other of the at least one of the base andintermediate frames is positioned when the intermediate frame is in thelowered position, the lift mechanism being positioned in a portion ofthe interior region located between the intermediate frame and the baseframe when the intermediate frame is in the lowered position.
 17. Thepatient support of, claim 16, wherein the base frame and intermediateframes include longitudinally extending members cooperating to define aspace therebetween and the lift mechanism is positioned in the space.18. The patient support of claim 17, wherein the longitudinallyextending members of the intermediate frame are spaced apart from acenter axis by a first horizontal distance, the longitudinally extendingmembers of the base frame are spaced apart from the center axis by asecond horizontal distance, and the lift mechanism is spaced apart fromthe center axis by a third horizontal distance, the third distance isgreater than one of the first and second distances and less than theother of the first and second distances.
 19. The patient support ofclaim 16, wherein the lift mechanism is configured to slide along atleast one of the base and intermediate frames during movement of theintermediate frame between the raised and lowered positions.
 20. Thepatient support of claim 16, wherein the intermediate and base framesnest together when the intermediate frame is in the lowered position.21. The patient support of claim 20, wherein a lower-most portion of theintermediate frame extends below an upper-most portion of the base framewhen the intermediate frame is in the lowered position.
 22. The patientsupport of claim 16, wherein portions of the lift mechanism arepositioned above the intermediate frame when the intermediate frame isin the lowered position.